Nissan Electrical Components Diagnosis and Repair (1)

REVISED MAREVISED MAREVISED MAREVISED MAREVISED MAYYYYY, 2003, 2003, 2003, 2003, 2003

ELTN9911B

ii

This book is designed for instructionaluse only for Nissan North America, Inc.and authorized dealer personnel. Foradditional information contact:

Nissan North America, Inc.Corporate Training OfficeTechnical Training18501 S. Figueroa St.Gardena, CA 90248-4500

© 2003 Nissan North America, Inc.

All rights reserved. No part of thispublication may be reproduced in any formwithout the prior written permission of thepublisher.

Printed in U.S.A.

First Printing: February, 1996Revised: May, 2003

This manual uses postconsumer recycled fibers

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Technical Training

Nissan North America, Inc. reserves the right to alter specifications or methods at any time.

iii

ELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPAIRAIRAIRAIRAIRTABLE OF CONTENTSTABLE OF CONTENTSTABLE OF CONTENTSTABLE OF CONTENTSTABLE OF CONTENTS

Section 1: TSection 1: TSection 1: TSection 1: TSection 1: Textextextextext

Electrical Component Diagnosis and Repair Overview .......................................................................... 1

Introduction ............................................................................................................................................... 1

General Precautions ................................................................................................................................ 2

Circuit Requirements ...................................................................................................................................... 3

Source, Load and Ground...................................................................................................................... 3

Circuit Protection Devices .................................................................................................................... 13

Circuit Controls ............................................................................................................................................. 17

Switch-Controlled Circuits .................................................................................................................. 17

Electrical Test Equipment ............................................................................................................................ 22

Analog Meters ......................................................................................................................................... 22

Digital Meters .......................................................................................................................................... 22

Ohmmeter Use ........................................................................................................................................ 23

Voltmeter Use .......................................................................................................................................... 25

Available Voltage .................................................................................................................................... 25

Voltage Drop ........................................................................................................................................... 26

Ammeter Use ........................................................................................................................................... 29

Relay Controlled Circuits ...................................................................................................................... 31

Meter and Gauge System ........................................................................................................................... 42

Spedometer Operation ......................................................................................................................... 43

Motors ............................................................................................................................................................. 44

Starting System ............................................................................................................................................ 45

Charging System Description .................................................................................................................... 49

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Electrical Diagrams ....................................................................................................................................... 51

Connector Symbols in Electrical Diagrams ...................................................................................... 55

Trouble Diagnosis Charts ..................................................................................................................... 61

Location of Electrical Units ................................................................................................................... 65

Foldout Circuit Diagrams ...................................................................................................................... 66

Using the Service Manual to Research Related Information ......................................................... 70

Electronically Controlled Circuits .............................................................................................................. 86

ECU Inputs .............................................................................................................................................. 87

Electronic Control Units (ECUs) ......................................................................................................... 88

Electrical Diagnosis ...................................................................................................................................... 93

Preliminary Diagnosis Tips .................................................................................................................... 94

On-Car Troubleshooting Tips .............................................................................................................. 94

Motors ....................................................................................................................................................104

Meter and Gauge Diagnosis ..............................................................................................................105

Meter and Gauge Check.....................................................................................................................107

Glossary of Terms.......................................................................................................................................109

v

Section 2: ExercisesSection 2: ExercisesSection 2: ExercisesSection 2: ExercisesSection 2: Exercises

Module 1 Locate Service Manual Information

Module 2 Intepret Service Manual Information

Module 3 Measuring Available Voltage

Module 4 Measuring Voltage Drop

Module 5 Measuring Resistance

Module 6 Measuring Current

Module 7 Combination Switch Operation

Module 8 Diagnosing One Transfer (1T) Relay Malfunctions

Module 9 Diagnosing One Make (1M) Relay Malfunctions

Module 10 Diagnosing Two Make (2M) Relay Malfunctions

Module 11 Diagnosing One Make-One Break (1M-1B) Relay Malfunctions

Module 12 Circuit Diagnosis Exercise #1






Module 18 How to Use a Digital Multimeter

Module 19 Fuel Gauge Tank Unit Testing

Module 20 Service Manual Electrical Symbols

Module 21 Testing Batteries, Starter and Charging Systems

vi

ELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPELECTRICAL COMPONENT DIAGNOSIS AND REPAIRAIRAIRAIRAIROBJECTIVESOBJECTIVESOBJECTIVESOBJECTIVESOBJECTIVES

Upon completion of this training program, you will be able to:

• Given an Electronic Service Manual (ESM), locate wiring diagram descriptions and interpretthe information as stated.

• Given an ESM, interpret wiring information/diagram symbols and answer related questions.

• Given a multimeter, a circuit simulator and a windshield wiper motor circuit, measureavailable voltage at different points in a circuit and make comparisons for the purpose ofdiagnosing faults.

• Given a voltmeter and a test circuit, measure voltage drop as specified and evaluate theresults against established specifications.

• Given a digital multimeter, a circuit simulator, a service manual, a fuel-injected vehicle andother components, measure resistance and compare to specifications.

• Given a digital multimeter, a circuit test kit with overlay #1, measure current flow through acircuit and evaluate the results.

• Given a combination switch and a combination switch circuit, read a combination switchchart and diagnose various combination switch circuits using a digital multimeter.

• Given a service manual (or ESM), a digital multimeter, a one transfer (1T) relay, circuit testkit with overlay #2, diagnose the operation of a 1T relay.

• Given overlay #3, a service manual and test equipment, test the operation of a vehicle with1M relay circuit.

• Given a service manual, a digital multimeter, a two make (2M) relay and a circuit test kit withoverlay #4, diagnose the operation of a 2M relay.

• Given a test kit with overlay #5, a service manual, digital multimeter and a one make-onebreak (1M-1B) relay, diagnose the operation of a 1M-1B relay.

• Given a customer's repair order, a service manual and digital multimeter, verify, isolate, repairand recheck the incident in question.

• Given a digital multimeter, electrical components and a car, identify the different meterfeatures, connect the test leads, and perform voltage, resistance, amperage and continuitytests.

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• Given a digital multimeter, service manual and an on-vehicle tank gauge unit, test theoperation of the fuel tank gauge unit and evaluate the test results.

• Given an ASIST/ESM workstation, identify and interpret the symbols used in electricalwiring diagrams.

• Given a vehicle, digital multimeter and model 620 tester, test the battery, starter andcharging system.

viii

NONONONONOTESTESTESTESTES

TEXT

1

ELECTRICAL COMPONENT DIAGNOSIS AND REPAIR OVERVIEW

Vehicles use electricity to control and operate many systems such as headlights, windshieldwipers and rear window defoggers. Today’s vehicles also use sophisticated control units andcircuits to add to driving comfort and the driver's control of the vehicle.

Despite the number of electrical circuits in a vehicle, troubleshooting and repair techniques usedon all circuits are relatively basic and straightforward, given some basic skills. To repair anelectrical problem correctly the first time, you must know how to troubleshoot and repair circuits.This course will provide you with the skills necessary to:

• Verify symptoms by attempting to operate circuits. Verify what is working and what is notworking.

• Isolate the source of the malfunction by:

- tracing current flow paths using wiring diagrams.

- locating harness connectors using harness layout diagrams.

- testing electrical circuits using a multimeter.

• Repair electrical problems by:

- fixing broken wires and poor connections.

- replacing broken components.

- adjusting a switch or sensor.

• Recheck to make sure the symptom is fixed. Duplicate conditions that caused theproblem, to be sure there are no new problems.

Introduction

The Electrical Component Diagnosis and Repair Course is a four day course covering diagnosisand repair of electrical systems. The Course begins with a review of electrical fundamentalsfollowed by a series of shop exercises. The following skills are emphasized:

• Reading wiring diagrams

• Circuit testing techniques

Each of the exercises will challenge your troubleshooting skills. The objectives for this coursewere carefully chosen to help you learn a more efficient way to diagnose electrical malfunctions.

INTRODUCTION

2

General Precautions

• Do not use electrical test equipment on any circuit related to the Supplemental RestraintSystem (SRS) unless instructed to do so by the service manual or your instructor. SRScircuits are identified by yellow insulation covering the wiring harnesses or yellow harnessconnectors.

• Do not operate the engine without adequate exhaust ventilation.

• Keep the work area well ventilated and free of any flammable materials. Take special carewhen handling any flammable or poisonous materials, such as gasoline, refrigerant gas,etc. When working in an enclosed area, be sure to properly ventilate the area beforeworking with hazardous materials.

• Do not smoke while working on the vehicle.

• Before elevating the vehicle, apply wheel chocks or other tire blocks to the wheels toprevent the vehicle from moving. With the vehicle parked on level ground, support it withsafety stands at the points designated for proper lifting or use a hoist to support andraise it if needed.

• Before starting repairs or circuit diagnosis which do not require battery power:

- Switch the ignition OFF.

- Disconnect the negative battery cable

• To prevent serious burns:

- Avoid contact with hot metal parts.

- Do not remove the radiator cap when the engine is hot.

• Before working on the vehicle:

- Use fender covers, seat covers and floor mats.

- Be careful that keys, belt buckles or buttons do not scratch painted surfaces.

• Do not touch the terminals of electrical components that are controlled electronically.Static electricity may damage internal electronic components.

INTRODUCTION

3

CIRCUIT REQUIREMENTS

Source, Load and Ground

The basis for discussing electricity in vehicles is the circuit. A circuit is a complete path forelectricity to flow. Electrical circuits consist of wires, wire connectors, switches, circuit protectiondevices, relays and electrical loads and grounds. The conventional current flow theory tracescurrent from the source to ground. Despite the complexity of the circuit or the number of parts inthe circuit, there are three essential elements all circuits must have to operate:

• Source (voltage)—The battery and the electrical path from the battery to the load. This isthe positive (+) side of the circuit.

• Load—Any electrical component that uses electrical energy to perform work. Examplesare lights, motors and defroster grids.

• Ground—The electrical path from the load back to the battery. This is the negative (–)side of the circuit.

If any of these essential elements is missing or not working, there is no current flow and thecircuit will not operate. Let's look at each of these elements.

Source (Voltage)

The source of voltage is the battery or alternator. The voltage source provides the energy topush current through the circuit, which makes it operate. The source side of the circuit includesall parts between the battery and the load. Refer to the battery rating charts (Page 46) at the endof the text section for recommended battery applications.

Load

A load is the device that produces heat, light, sound or motion when the circuit is operating. Lightbulbs, motors and heating elements, such as cigarette lighters and rear window defoggers, aretypical electrical loads. A load always has resistance and consumes (uses up) voltage when thecircuit is ON.

Ground

A ground completes the circuit from the load back to the negative battery post. Notice that aground path is always on the other side of the load. As important as the ground is, it is the partof the circuit that is most often overlooked.

WireBattery Wire Load

Source side of circuit Ground side of circuit


4

Perhaps a reason for this is that technicians often think that circuit grounds consist of separatewires. Using a separate ground wire to connect each vehicle circuit to the battery is not practical.Most electrical circuits complete the ground path directly to the vehicle chassis or body.

¨Load

Battery

Negative –

Ground

When source, load and ground are all operating correctly, a complete path for current flow exists.This is a complete (or closed) circuit. An open circuit occurs when the electrical path isinterrupted. This might occur when a switch is open, a light bulb burns out, a wire breaks or awire connector becomes disconnected.

Voltage, Amperage and Resistance

Working circuits contain these three electrical elements:

• Voltage - The electrical pressure that pushes current through the circuit.

• Amperage - Flow of current moving in a circuit.

• Resistance - Opposition to the flow of current.

Voltage (Symbol: V)

Voltage is the electrical pressure that pushes current through a circuit. Nissan and Infiniti vehiclesall use 12 volt batteries, but the system operates at up to 14.7 volts while the engine is running.The charging system provides the additional voltage to keep the battery charged.

Electricalcurrent

Voltage = Electrical pressure


5

Amperage (Symbol: A)

Amperage is the measurement of current flow in a circuit. Current does not flow unless voltage ispresent to push it through a circuit.

Research in chemistry and physics has established the electron theory to help explain whatelectricity is and how it is used.

The electron theory states that all matter is made up of atoms. Atoms contain three types ofsmaller particles called:

• Protons

• Neutrons

• Electrons

Protons, which have a positive electrical charge, combinewith neutrons (which have no electrical charge), to form thecenter or nucleus of the atom. Electrons have a negativeelectrical charge and orbit around the nucleus, much like theplanets in our solar system orbit around the sun.

Certain materials such as copper and steel contain free electrons which can be pushed from oneatom to the next. This movement of electrons occurs in one direction, creating a chain reaction.The chain reaction in which free electrons move from one atom to the next is called current flowor electricity.


6

Resistance (Symbol: )

Resistance opposes current flow in a circuit and is measured in Ohms.

Resistors are electrical devices that restrict current flow in a circuit. Because they restrict currentflow, voltage decreases as current is pushed through a resistor. Two types of resistors are usedin automotive circuits. A fixed resistor has a set resistance in a circuit. A variable resistor, such asa dimmer control, changes the amount of current flow by mechanically changing its resistance.

Earlier, we spoke of a circuit's requirements for source voltage, load and ground. The load is thedevice that provides heat, light, or motion. When the resistance of the circuit load is in the normalrange, with power applied and a ground connected, the circuit operates as designed. However,if either the source, load or ground is out of balance, the circuit will malfunction.

For example, suppose the battery voltage drops below the normal range. Circuits such as thestarting circuit cannot operate as designed. In such cases, the customer may complain of hardstarting.

• Malfunctions occur when resistance in a circuit increases or decreases abnormally.

• Increased circuit resistance can be caused by loose connections, corroded wireconnectors or dirty switch contacts. These conditions create unwanted resistance thatreduces the normal flow of current needed to operate the load. This causes bulbs to be dimand motors to turn slowly because voltage is used up by the unwanted resistance—thecircuit has to work harder.

• Decreased circuit resistance increases current flow in a circuit. This can be caused by apartially shorted load. The result is a blown fuse. In some cases, higher than normal currentflow can overheat and burn wires and connectors.

Switch

Battery

Light bulb

Variable resistor


7

The following chart summarizes the terms we’ve just described. We'll discuss circuit diagnosis ina later section of this manual.

Term Definition Unit of Measure Symbol

Voltage (E) Electrical pressure Volt V

Amperage (I) Current flow Amp A

Resistance (R) Opposition to current flow Ohm

Conductors

Conductors are devices such as wires, that provide a path for current to flow. Some materialsconduct electricity much better than others. Copper and steel are good conductors. Gold andsilver are even better conductors because they have even more orbiting electrons. Since goldand silver are quite expensive, they are used sparingly on circuits such as the SupplementalRestraint System (SRS).

Insulators

Materials which do not conduct electricity are called insulators. Materials such as wood, glass,rubber and plastic are some examples of insulators. These materials are made of atoms whoseelectrons are very tightly bound to the nucleus and cannot easily move to other atoms. In vehiclewiring harnesses, the insulation isolates each wire so current flows only through the intendedpath.

BestBestBestBestBestBestBestBestBestBest

ConductorsConductorsConductorsConductorsConductors InsulatorsInsulatorsInsulatorsInsulatorsInsulatorsG

oldG

oldG

oldG

oldG

oldCopper

Copper

Copper

Copper

Copper

Silver

Silver

Silver

Silver

Silver

Aluminu

m

Aluminu

m

Aluminu

m

Aluminu

m

Aluminu

m

Steel

Steel

Steel

Steel

Steel

Lead

Lead

Lead

Lead

Lead

AirAirAirAirAir

Ceram

ic

Ceram

ic

Ceram

ic

Ceram

ic

Ceram

ic

Rubber

Rubber

Rubber

Rubber

Rubber

Plast

ic

Plast

ic

Plast

ic

Plast

ic

Plast

ic


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Ohm’s Law

In 1826, a German physicist named Georg Ohm developed a theory about electricity. Simplystated, there is a relationship between voltage, resistance and amperage. To apply this in apractical sense, consider the following two examples:

1. If voltage (volts) stays constant and circuit resistance (Ohms) increases, current flow(amps) decreases.

2. If voltage stays constant and circuit resistance decreases, current flow increases.

CauseCauseCauseCauseCause EffectEffectEffectEffectEffect

Corrosion Dim bulb

Loose ground Fan runsslow

CauseCauseCauseCauseCause EffectEffectEffectEffectEffect

Short circuit Fuseblows,circuitstopsworking

Resistance(Ohms)

Current flow(Amps)

12 Volts(constant)

Current flow(Amps)

Resistance(Ohms)

12 Volts(constant)


9

Circuit Types

As previously stated, all circuits must have source, load and ground to operate properly. The wayin which these circuit elements are put together can be classified as either parallel, series, orseries-parallel.

Series Circuits

In a series circuit, the source, load and ground are arranged so current has only one path throughthe circuit. Thus, the current flow (amps) will be the same no matter where it is measured in thecircuit. However, voltage in a series circuit decreases as current passes through each load.

NoteNoteNoteNoteNote: If the resistance of the loads are equal, the available voltage divides equally between theloads.

A series circuit will operate if there are no opens in the circuit. In the circuit above, if the switchfails (creating an open circuit), no current will flow and neither bulb will light.

TTTTTroubleshooting Tip #1:roubleshooting Tip #1:roubleshooting Tip #1:roubleshooting Tip #1:roubleshooting Tip #1:An open at any point in a series circuit will prevent the entire circuit from operating.

Battery

Ground

Source Switch

Load #1 Load #2

Ground

Current flows...Current flows...Current flows...Current flows...Current flows...

in one pathin one pathin one pathin one pathin one path


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Parallel Circuits

In a parallel circuit there are two or more paths for current to flow to ground. The tail light circuitis an example of a parallel circuit. If one of the bulbs in a parallel circuit burns out, current willcontinue to flow through the other path in the circuit and the other bulb(s) will still operate. In theexample below, if one of the bulbs does not work, current will continue to flow through the otherpath in the circuit and the other bulb will still light.

Ground Ground

SourceSwitch

Load #1

Load #2 Parallel branches

TTTTTroubleshooting Tip #2:roubleshooting Tip #2:roubleshooting Tip #2:roubleshooting Tip #2:roubleshooting Tip #2:An open circuit in a parallel branch prevents only the load in the open path from operating.


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Series-Parallel Circuits

Besides series and parallel circuits, some vehicles also have series-parallel circuits. A series-parallel circuit is a combination of the two circuit types. The parallel part of the circuit (load 1 and2) can be diagnosed as a parallel circuit while the series part of the circuit (load 3) is diagnosedthe same way as a series circuit.

Ground

Battery

Switch

Load #1

Load #2

Ground

Load #3Dimmer Control

(variable resistor)

Series-parallel circuits typically contain a dropping resistor either before the circuit branches or inthe ground side of the circuit after the loads. One common example of a series-parallel circuit isthe dash light circuit. The dimmer control (variable resistor) is installed in series between theparallel loads (bulbs) and the circuit ground.


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In a parallel circuit, if the resistance of each bulb is the same, current flow will be the same. Ifresistance changes in any of the paths, current flow through that path will also change. A badconnection at one of the bulbs will change the resistance for only that one bulb. In the examplebelow, high resistance causes load #2 to glow dimly, but load #1 operates normally.

Vehicles use parallel circuits so each load has the same available voltage to operate it. Thesecircuits typically branch out from the fuse box.

Ground

Battery

Source Switch

Load #1

Load #2

GroundConnection withhigh resistance

TTTTTroubleshooting Tip #3:roubleshooting Tip #3:roubleshooting Tip #3:roubleshooting Tip #3:roubleshooting Tip #3:An open in a parallel circuit only affects the operation of the load in the “open” branch.However, if a problem occurs before the circuit branches, it will affect both loads. If one orboth loads operate poorly, look for high resistance in circuit connections.


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Circuit Protection Devices

There are three types of circuit protection devices. They are fuses, fusible links and circuitbreakers.

Fuses, Fusible Links and Circuit Breakers

Most electrical circuits use protection devices such as fuses, fusible links and circuit breakers.Circuit breakers open when excess current flow causes them to overheat. They reset after acool-down period. Fuses and fusible links are thin wires that melt very easily when overheated byexcessive current flow. Fuses and fusible links are built-in weak spots designed to protect circuitcomponents and wiring from damage. Fuses fail because of two conditions: short circuits andgrounded circuits.

• A crossover circuitA crossover circuitA crossover circuitA crossover circuitA crossover circuit (short to voltage) occurs when two different circuit conductorselectrically touch each other. This occurs when a bare wire from one circuit touches a barewire from another circuit. Such conditions may cause wiring to overheat or fuses to melt ifthe resulting current flow is greater than designed into either circuit. Normal circuitswitching is no longer effective when this condition occurs.

• A short-to-groundA short-to-groundA short-to-groundA short-to-groundA short-to-ground occurs when current bypasses the circuit load and goes directly toground. When this occurs, the resistance in the circuit is so low that current increasesabove the rating of the fuse protecting the circuit and the fuse melts. Never substitute ahigher amperage rating fuse when this condition occurs because wiring will surely melttogether as a result of higher than normal current flow.

Wire insulationConductor

Short to voltage

Bare conductors touch and fuse melts to protect circuit

Wire insulationConductor

Short to ground

Bare conductor touches and fuse melts to protect circuit

Chassis GroundChassis GroundChassis GroundChassis GroundChassis Ground


14

Fuses

Fuse ratings are based on the current flow needed to operate the circuit while protecting it fromexcessive current flow. For example, a circuit that normally draws 6 amps might have a 10 ampfuse to protect it.

If you replace one fuse with another that has a higher than recommended rating, a short circuit(resulting in excessive current flow) could damage circuit components before the fuse melts.Never substitute a fuse with a rating different than specified for that circuit. Refer to the label onthe fuse panel for the correct application.

Blade-type fuses have a high resistance to shock and vibration and greater durability once inservice. The fuse material of blade fuses is molded into the colored plastic. The current rating ismolded into the top of the fuse. The color also indicates the current rating.

Fusible Links

Fusible links also protect against excessive current flow.They protect circuits between the battery and the fuseblock. Like fuses, fusible links use different colors toidentify the amperage ratings of fusible links. The chart onthe opposite page shows the common sizes.

TTTTTroubleshooting Tip #4:roubleshooting Tip #4:roubleshooting Tip #4:roubleshooting Tip #4:roubleshooting Tip #4:Fuses and fusible links blow because of increasedcurrent flow (reduced resistance) in the circuitbetween SOURCE and GROUND.

Fuse ColorFuse ColorFuse ColorFuse ColorFuse Color Current RatingCurrent RatingCurrent RatingCurrent RatingCurrent Rating

Green 30 amps

Yellow 20 amps

Blue 15 amps

Red 10 amps

Brown 7.5 amps


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Fusible links:

• Protect high current, direct load circuits such as the radiator fan.

• Provide current for multiple fused circuits (see illustration, next page).

• Are only found on the source side of the circuit, never on the ground side.

TTTTTroubleshooting Tip #5:roubleshooting Tip #5:roubleshooting Tip #5:roubleshooting Tip #5:roubleshooting Tip #5:If an unwanted ground occurs on the GROUND side of the a LOAD in a ground-switchedcircuit, the LOAD will stay ON all the time.

TTTTTroubleshooting Tip #6:roubleshooting Tip #6:roubleshooting Tip #6:roubleshooting Tip #6:roubleshooting Tip #6:Blown fuses often result after body or other major repairs to a vehicle. Always check forpinched wires in areas where repairs have recently been performed.

Circuit Breakers

Circuit breakers are circuit protection devices that open when excessive current flow causesthem to overheat. The contacts close again after the circuit breaker cools down. Some circuitsare equipped with circuit breakers that protect multiple circuits. See the power supply routingillustration that follows.

Current to meltCurrent to meltCurrent to meltCurrent to meltCurrent to meltColorColorColorColorColor Continuous Current FlowContinuous Current FlowContinuous Current FlowContinuous Current FlowContinuous Current Flow fusible link within 5 sec.fusible link within 5 sec.fusible link within 5 sec.fusible link within 5 sec.fusible link within 5 sec.

Brown 15 amps About 120 amps

Green 20 amps About 200 amps

Red 25 amps About 250 amps

Black 33amps About 300 amps


16

NoteNoteNoteNoteNote: Fuses and fusible links melt because of increased current flow (reduced resistance) in thecircuit.

Placing fusible links on the source side of a circuit will prevent wires from overheating.

Fusible links Fuses

Circuit breakerprotects multiple

circuits


17

CIRCUIT CONTROLS

So far, we’ve discussed circuit requirements (source, load and ground) and circuit arrangements(series, parallel and series-parallel). Electrical circuits are controlled by three different devices.They are:

1. Switches

2. Relays

3. Electronic devices (such as the Engine Control Module). These will be covered later.

Switch-Controlled Circuits

Even though the only requirements for a circuit to operate are a power, load and ground, mostcircuits are a little more complex. Switch-controlled circuits contain wires, connections, relays,motors, bulbs and a switch.

Switches control either the source or ground side of the circuit. Some switches are manuallyoperated. Some switches are temperature controlled, and yet others are controlled by pressure.No matter what type of switch is used, there are three important points to remember:

1. Switches are not loads.

2. Switches are wired in series with the circuit.

3. Switches can be located on the source or the ground side of the load.

TTTTTroubleshooting Tip #7:roubleshooting Tip #7:roubleshooting Tip #7:roubleshooting Tip #7:roubleshooting Tip #7:If an entire circuit is dead, the problem is with a series component such as a switch orSOURCE, wiring connections, faulty load or the GROUND.

CIRCUIT CONTROLS

18

Switch Positions

Switches are shown in wiring diagrams as if the vehicle is in the ¡°normal¡± condition. A vehicle isin the “normal” condition when:

• Ignition switch is OFF

• Doors, hood and trunk lid/back door are closed

• Pedals are not depressed, and

• Parking brake is released

Normally Open Switch(NO)

Normally Closed Switch(NC)

CIRCUIT CONTROLS

19

The following switches are normally open (NO): Brake pedals (usually not depressed), doors(usually closed), hoods (usually down), parking brakes (usually released).

The front door switches in the diagram below are “normally open” (NO) switches. When thedoors are closed, both switches are open and the interior light is OFF. If the door switchcontacts were to close (interior light ON) when the door closes, it would be classified as a“normally closed” (NC) switch.

Normally Open (NO)switches

(manually switchable)

Door position

CIRCUIT CONTROLS

20

Multiple Position Switches

Multiple position switches are similar to single contact switches. However, multiple switchesconnect more than one circuit so that separate devices (loads) can operate at the same time.

For example, the wiper switch is a multiple switch. It can make different contact pointconnections to perform multiple functions.

High beam

Low beam

Flash-to-passLeft turn

OFF

ON

ONOFF

FOG LAMP

HEADLIGHT

TURNRight turn

N OFF

INT

LO

HI

WASH

The wiper switch has several positions—OFF, INT, LO, HI and WASH. These positions are listedacross the top of the wiper switch chart that follows. The numbers along the left-hand side ofthis chart identify each of the terminals housed in the switch connector. These numbers aremolded into the plastic housing of the wiper switch next to each of the switch terminals.

The circles and interconnecting lines indicate the connections inside the switch.

• Circles show the internal connections in each switch position.

• Line between the circles show terminal connections for each switch position.

NoteNoteNoteNoteNote: For example: In the LO switch position, only terminals #14 and #17 are connected orhave continuity.

OFF Switch OpenINT Intermittent (delay)LO Constant Low SpeedHI Constant hight speedWASH Washers ON

Switch positions

Continuity points

Switch terminalidentification

numbers

Wiper Switch ChartWiper Switch ChartWiper Switch ChartWiper Switch ChartWiper Switch Chart

CIRCUIT CONTROLS

21

To understand the wiper switch circuit above, simply read down the column which identifies aparticular switch position to see which terminals are connected by the circles and lines. Thenread the corresponding circuit terminal numbers in the far left column. The shaded exampleshows terminals 14 and 17 connected when the switch is in the LO position.

Using the above chart for reference, identify the connected terminals for the other switchpositions:

Switch positions

Continuity points

Switch terminalidentification

numbers

Wiper SwitchWiper SwitchWiper SwitchWiper SwitchWiper Switch

Switch Position Switch Position Switch Position Switch Position Switch Position Switch TSwitch TSwitch TSwitch TSwitch Terminalserminalserminalserminalserminals

WASH and

HI and

INT and

OFF and

CIRCUIT CONTROLS

22

ELECTRICAL TEST EQUIPMENT

There are two categories of test meters available for automotive electrical testing: analog anddigital. These categories refer to the type of meter display. The most common meter forautomotive testing is actually three meters in one. It is called a digital multimeter (DMM). Thethree meters built into a multimeter are:

• Ohmmeter Measures resistance ( )

• Voltmeter Measures voltage (V)

• Ammeter Measures current flow in amps (A)

Analog Meters

Analog meters use a calibrated scale with a pointing needle to indicate the value of themeasurement being made. The needle points to the position on the scale. Analog meters haveserious limitations when used to test modern automotive computer-controlled circuits. Becauseof their low internal impedance (resistance), electronic control units may be damaged fromincreased current flow caused by connecting the meter in parallel. For this reason, they are notrecommended for testing automotive electrical systems.

Digital Meters

Digital meters display a digital readout of the measurement being made. Use high impedancedigital multimeters to test automotive electrical circuits. The more reliable digital multimeters havean input impedance of 10 megaohms or more.

Analog MeterAnalog MeterAnalog MeterAnalog MeterAnalog Meter


23

Digital Multimeter (DMM) Safety Checklist:

• Use a meter that meets accepted safety standards.

• Use a meter with fused current inputs. Be sure to check fusesbefore making current measurements.

• Inspect test leads for physical damage before making ameasurement.

• Use the meter to check continuity of the tests leads.

• Only use test leads that have shrouded connectors and fingerguards.

• Only use meters with recessed input jacks.

• Select the proper function and range for the measurement youintend to make.

• Be certain the meter is in good operating condition.

• Follow all equipment safety precautions.

• Always disconnect the red (+) test lead first.

• Use a meter which has overload protection on the Ohms function.

• When measuring current without a current amp clamp, turn the power OFF beforeconnecting into the circuit.

• Use extreme caution in high current and high voltage testing situations. Use the appropriateequipment, such as high voltage probes and high current clamps, for your personal safety.

Ohmmeter Use

An ohmmeter has two important functions:

• Measuring circuit or component resistance.

• Checking continuity in a circuit or a component.

Most ohmmeters have different measuring ranges. If you don’t know the resistance, start on thehighest test scale first, then switch to a lower scale to obtain the most accurate reading. Mostmodern DMMs set the measurement range automatically (autorange).


24

CAUTION:

NEVER USE AN OHMMETER ON A CIRCUIT WHILE IT IS OPERATING. THISCOULD DAMAGE THE METER.

To use an ohmmeter:

Step 1: Set the meter to measure resistance(Ω).

Step 2: Check meter calibration by touching thetwo test leads together. Typical test leadresistance is between 0.2 and 0.5 Ω.

Step 3: Be sure the circuit being checked isswitched OFF. Never use an ohmmeteron a circuit while it is operating. Theohmmeter has an internal battery.Additional voltage through the m eter maydamage it if the meter does not haveoverload protection.

Step 4: Connect the meter leads to the ends ofthe circuit or component to test and readthe resistance.

NoteNoteNoteNoteNote: Take two (2) separate readings and comparethem to determine how good the ground is.

Non auto-ranging meters require you to multiplyyour reading based on the scale selected.

For example:

Rotary switch

Sending unit

1st

2nd


25

Voltmeter Use

A voltmeter is the most commonly used and most versatile of all automotive electrical testers. Avoltmeter has two functions:

• Measuring circuit voltage

• Measuring voltage drop

To measure voltage:

Step 1: Set the meter to measure voltage:DC (V ) or AC (V~). If circuit voltage isunknown, use the scale closest to, buthigher than, 12 volts.

Step 2: Connect the voltmeter probes in parallelacross the circuit to obtain a voltagereading. Observe the polarity of the meterwhen making these connections. In otherwords, connect the red lead to the pointclosest to the battery and the black leadto the connection toward ground.

Step 3: Operate the circuit being checked andread the voltage in the display window.

Available Voltage

Checking for available voltage measures the voltage available up to the location of the circuit towhich the meter is connected. In a normal circuit, there should be source (battery) voltageavailable up to the load. Since the battery provides a constant 12 volts or more, any excessiveresistance in the circuit will reduce the available voltage to operate the load. Reduced availablevoltage results in dim light bulbs, slower spinning motors and relay coil circuits that don't haveenough “energy” to close the contacts.

TTTTTroubleshooting Tip #8:roubleshooting Tip #8:roubleshooting Tip #8:roubleshooting Tip #8:roubleshooting Tip #8:You can also use a test light to test high current, NON-ELECTRONIC circuits. A test lightcan test bulb circuits, relay circuits and fuses for available voltage. However, a test lightCANNOT measure the amount of available voltage, a decided disadvantage.

DC volts


26

Voltage Drop

Perhaps the biggest electrical problem faced by technicians is that of unwanted voltage drop in acircuit. All loads in a circuit have resistance and use voltage. However, voltage drop can alsooccur in other parts of a circuit, such as at connection points, and this can affect circuitoperation. A voltage drop test is a way of measuring the voltage used by an individual circuit loador connections within the circuit. The voltage drop measurement tells you how much voltage isused between the meter test leads.

Rule of Thumb for Voltage Drops at Connections

NoteNoteNoteNoteNote: Maximum allowable voltage drops:Wire Connections less than 0.1 VoltsGround Connections 0.1 VoltsSwitch Contacts 0.3 VoltsStarter Solenoids 0.5 Volts

Each resistance in a circuit uses voltage, so a voltmeter can isolate circuit malfunctions bymeasuring the voltage drop in a selected part of the circuit.

Earlier, we said that a switch is not a load. However, during diagnosis, use a voltmeter tomeasure voltage at each of the switch contacts. This will indicate whether the switch is makingand breaking contact as it should. A voltage drop across the closed contacts indicates excessiveresistance and will cause the circuit to operate incorrectly.

TTTTTroubleshooting Tip #9:roubleshooting Tip #9:roubleshooting Tip #9:roubleshooting Tip #9:roubleshooting Tip #9:The greater the resistance in any part of a circuit, the greater the voltage drop.


27

Look at the wiring in this drawing. If an ohmmeter were connected as shown, the single strand ofwire still making contact would give an ohmmeter reading of near 0 (zero) ohms (no resistance)indicating a good circuit. However, during circuit operation this single strand of wire cannot carrythe amperes necessary for the circuit to operate properly. While the ohmmeter's low resistancegives the indication that there is continuity, the single strand of wire impedes current flow.Therefore, a voltage drop occurs at this point in the circuit.

Important Note:Important Note:Important Note:Important Note:Important Note:Unwanted resistance can take many forms. For example, water can cause corrosioninside a wire connector. This creates excessive resistance that reads on the voltmeter asa voltage drop. Likewise, dirty or corroded switch contacts and loose wire connectionscan produce unwanted resistance and cause a voltage drop.

TTTTTroubleshooting Tip #10:roubleshooting Tip #10:roubleshooting Tip #10:roubleshooting Tip #10:roubleshooting Tip #10:When isolating circuit problems, perform tests that:

- You can do quickly- You can do easily- Tell you most about the problem


28

Inline Voltage Drop

To measure voltage drop:

a = b + c + d + e + fa = b + c + d + e + fa = b + c + d + e + fa = b + c + d + e + fa = b + c + d + e + f

Step 1: Connect the voltmeter across the connection or portion of the circuit to be tested.The positive lead of the voltmeter should be close to source and the negative leadclose to ground.

Step 2: Operate the circuit.

Step 3: The voltmeter will indicate how many volts are used by that part of the circuit.

Voltage drop can occur in any part of a circuit. Because a circuit must have source, load andground to operate, check the ground side of a load for voltage drop as well. Look for bad groundconnections at the vehicle frame, corrosion at the negative post of the battery and loose groundstraps or connections at components such as the starter motor and alternator.

Battery(source)

Switch

Excessive Vdrop

Connectionwith a highresistance

V

V V V

V

V


29

Ammeter Use

An ammeter measures current flow in a circuit. If specifications are available, amperage (current)readings can be helpful during diagnosis. Starter current draw (amperage) readings are listed inthe Service Data and Specifications of the service manual. However, amperage specifications arenot available for most other electrical circuits.

To measure current:

Step 1: Connect the ammeter in series in the circuit. This means that all the current flowingin the circuit will flow through the meter. Some hand-held meters can only measureup to 2 amps. Some meters have the capability to measure up to 10 amps.

CAUTION:

THE AMMETER IS NOW PART OF THE CIRCUIT AND EXCESSIVE AMPERAGE,SUCH AS MIGHT OCCUR IN A SHORT CIRCUIT, CAN DAMAGE THE AMMETERFUSE. ALWAYS CHECK FUSES ACCORDING TO THE METER INSTRUCTIONS.

Step 2: Be sure the positive lead of the ammeter is toward the battery plus (+) terminaland the negative ammeter lead connects to the ground or negative (–) side of thecircuit.

Step 3: Switch the circuit ON. An amperage reading above specifications indicates lowcircuit resistance. A lower than normal current reading could be caused by a weakbattery, defective charging system or high circuit resistance.

NoteNoteNoteNoteNote: Many ammeters have an inductive pickup instead of separate ammeter leads. Inductiveammeters are both accurate and easy to use without becoming a part of the circuit.

A Ammeter reads circuit current

Connect ammeter to circuit atfuse or switch to measure total

circuit currentBattery

Load


30

Kent-Moore J-44373 Model 620 Tester

This tester is used to test batteries, starters and chargingsystems. It uses the conductance method to determine thebattery's ability to produce voltage. Conductance is ameasure of the plate surface available in the battery todetermine how much voltage the battery can produce.

To determine the battery conductance, the tester produces asmall signal which is sent through the battery. The tester thenmeasures a portion of the AC current response. The testercan test a battery exactly as received without having torecharge it before testing. Because no loads are applied tothe battery, the test is completely safe. The results provide agood indication of the battery condition based on the resultsin the chart below. In some cases, the tester may recommenda charge and retest.

WARNING:

NEVER RECHARGE A BATTERY IF THE TESTER INDICATES THERE ARE BAD CELLS.DOING SO COULD CAUSE THE BATTERY TO EXPLODE AND INJURE YOU AND/ORANYONE NEARBY.

NoteNoteNoteNoteNote:• Record output codes for each test on the work order.• Record date and time before performing tests.

J-44373 TJ-44373 TJ-44373 TJ-44373 TJ-44373 Test Resultsest Resultsest Resultsest Resultsest Results

Battery TBattery TBattery TBattery TBattery Testsestsestsestsests Starter TStarter TStarter TStarter TStarter Testsestsestsestsests Charging System TCharging System TCharging System TCharging System TCharging System Testsestsestsestsests

• Good battery

• Good, but needsrecharge

• Fully charge battery,then retest

• Replace battery andretest

• Bad cell detected

• Cranking voltage normal

• Cranking voltage low(starter suspected)

• Charge battery(insufficient charge fortest)

• Replace battery

• Charging system dioderipple normal

• Charging systemincident caused by:

- No charging voltage- Low charging voltage- High charging voltage- Excess ripple detected


31

Relay Controlled Circuits

Relays are used to connect two parts of a circuit, much like a switch, by using low amperage(thin) wires to control a higher amp circuit. However, a relay is not operated mechanically like theother switches we discussed. Inside the relay housing there are two circuits: the control circuitand the contact circuit. The control circuit contains a coil of fine wire which, when energized,develops a magnetic field. The contact circuit contains a spring-loaded switch arm that connectsthe relay contacts when the control circuit is energized. The magnetic field pulls the contactsclosed.

Relays have two separate circuits:

• Coil control (low current) circuit

• Contact (high current) circuit

Control circuit (lowcurrent)

Contact circuit (highcurrent), not yet connected

To circuit load

Source

Relay housing

Ground through ECM orexternal switch

Source voltage to highcurrent circuit


32

Like switches, relays can have normally open (NO) or normally closed (NC) contacts. In wiringdiagrams, hollow circles represent normally open relay contacts. Darkened circles representnormally closed relay contacts. Refer to the following chart for more details.

Some relays have a single contact point circuit and others have two. Some relays have onlynormally open contacts, while others have a combination of normally open and normally closedcontacts. The circuit design dictates the type of relay to use.

NO and NC RelaysNO and NC RelaysNO and NC RelaysNO and NC RelaysNO and NC Relays Not EnergizedNot EnergizedNot EnergizedNot EnergizedNot Energized Energized Energized Energized Energized Energized

Normally OpenNormally OpenNormally OpenNormally OpenNormally Open(NO) Relay(NO) Relay(NO) Relay(NO) Relay(NO) Relay

Normally ClosedNormally ClosedNormally ClosedNormally ClosedNormally Closed(NC) Relay(NC) Relay(NC) Relay(NC) Relay(NC) Relay

Does not flow

Switch 1 Battery

Flows

Switch 1 Battery

Flows

Switch 1 Switch 1Battery Battery

Does not flow


33

There are four types of relays used on vehicles:

1. 1M (One-Make Relay)

2. 1T (One-Transfer Relay)

3. 2M (Two-Make Relay)

4. 1M-1B (One-Make, One-Break Relay)

To identify the connections used with each of the relays, a small diagram showing each of theterminal numbers is molded into the top of the relay. On the bottom of each relay, terminalnumbers are shown next to each terminal.


34

1M (One-Make) Relay Operation

The “1M” relay has four terminals in a single connector. Relays of this type are enclosed in eithera blue, green or yellow housing depending on the amperage rating of the contact point circuit.The green relay is normally found on a ground circuit.

Wire terminals #1 and #2 of the 1M relay connect the coil to an external control. When currentflows through this circuit, a magnetic field develops causing the contacts between terminals #3and #5 to close. This high current circuit connects the load to source or ground to complete thecircuit.

TTTTTroubleshooting Tip #11:roubleshooting Tip #11:roubleshooting Tip #11:roubleshooting Tip #11:roubleshooting Tip #11:Although the configuration of the blue, green and yellow relays is the same, do notinterchange them. They have different operating specifications.

1-M Relay and Symbols Used1-M Relay and Symbols Used1-M Relay and Symbols Used1-M Relay and Symbols Used1-M Relay and Symbols Used Color Code: Blue, Green or YColor Code: Blue, Green or YColor Code: Blue, Green or YColor Code: Blue, Green or YColor Code: Blue, Green or Yellowellowellowellowellow

Bottom view Circuit diagram Wiring diagram


35

Relays plug into wire connectors or relay sockets. The service manual identifies each relay socketwith a connector number. In the following fog lamp relay circuit, the connector number is E49.

In the following wiring diagram:

• The P/L (pink with blue stripe) wire (terminal #1) and the G/OR (green with orange stripe)wire (terminal #2) are connected to the coil control circuit.

• The OR (orange) wire (terminal #3) and the OR/B (orange with black stripe) wire (terminal#5) are connected to the contact circuit.

Relay and relay socketRelay and relay socketRelay and relay socketRelay and relay socketRelay and relay socketconnector numberconnector numberconnector numberconnector numberconnector number

E49E49E49E49E49

1M Relay1M Relay1M Relay1M Relay1M Relay


36

1T (One Transfer) Relay Operation

The 1T relay has a black housing with five wire terminals. It operates like the 1M type relays withone exception. There is normally contact between terminals #3 and #4 until the relay isenergized. When energized, current then flows from terminal #3 through terminal #5.

1-1-1-1-1-T Relay and Symbols UsedT Relay and Symbols UsedT Relay and Symbols UsedT Relay and Symbols UsedT Relay and Symbols Used Color Code: BlackColor Code: BlackColor Code: BlackColor Code: BlackColor Code: Black



37

1T Relay1T Relay1T Relay1T Relay1T Relay

1T Relay1T Relay1T Relay1T Relay1T Relay


38

2M (Two-Make Relay) Relay Operation

The 2M relay has a brown housing and is similar to the 1M type relay. However, the 2M relaycompletes two separate circuits when the coil control circuit is energized.

Terminals #3 and #5 connect one circuit and terminals #6 and #7 connect the other. 2M relaysare used to divide current flow through two sets of contact points when high current flow mayburn the contacts in a 1M relay.

2-M Relay and Symbols Used2-M Relay and Symbols Used2-M Relay and Symbols Used2-M Relay and Symbols Used2-M Relay and Symbols Used Color Code: BrownColor Code: BrownColor Code: BrownColor Code: BrownColor Code: Brown


A malfunction with a 2M relay can:

• Prevent both loads from operating if the malfunction occurs in the coil control circuit.

• Prevent one of the loads from operating if the malfunction occurs in either of the contactpoint circuits.


39

In the following Rear Window Defogger circuit, two sets of contacts close at the same timewhen the coil control circuit is energized. This provides two current paths to the rear windowdefogger.




40

1M-1B (One-Make, One-Break) Relay Operation

The fourth type of relay, housed in a gray case, is the 1M-1B type relay. When the coil controlcircuit of a 1M-1B relay is not energized, continuity exists through the normally closed contactpoint circuit between terminals #3 and #4. When the coil control circuit between terminals #1and #2 is energized, the circuit connecting terminals #3 and #4 opens. At the same time, thenormally open contact point circuit between terminals #6 and #7 closes, allowing current to flow.

1M-1B Relay and Symbols Used1M-1B Relay and Symbols Used1M-1B Relay and Symbols Used1M-1B Relay and Symbols Used1M-1B Relay and Symbols Used Color Code: GrayColor Code: GrayColor Code: GrayColor Code: GrayColor Code: Gray


If the coil control circuit fails:

• the normally closed circuit connecting terminal #3 to #4 will not open.

• the normally open circuit between terminal #6 and #7 will not close.


41

1M-1B Relay1M-1B Relay1M-1B Relay1M-1B Relay1M-1B Relay

1M-1B Relay1M-1B Relay1M-1B Relay1M-1B Relay1M-1B Relay

This circuitThis circuitThis circuitThis circuitThis circuitmust bemust bemust bemust bemust beenergized toenergized toenergized toenergized toenergized tostart enginestart enginestart enginestart enginestart engine

In the following circuit, the inhibitor switch must be either in ¡°P¡± or ¡°N¡± to complete theground for the coil control circuit. This would then connect the contacts between terminal #6 and#7 allowing the engine to start.


42

METER AND GAUGE SYSTEM

System Operation Overview

Automotive gauges display temperature, pressure or quantity. Most Nissan and Infiniti vehiclesuse “needle type” gauges.

Instrument gauges activate when the ignition is switched ON. Needle-type gauges contain acircuit that consists of a coil of wire connected in series to a sending unit, which is attached tothe object to measure. The sending unit is a resistor. Its resistance changes according to whatthe gauge is designed to monitor (oil pressure, coolant temperature, fuel level, etc.). For example,in a temperature gauge, when the engine temperature is high, the resistance in the sending unit(and the circuit) is low. The voltage in a variable resistance circuit changes the magnetic field inthe gauge coil, which changes the position of the needle pointer. The scale in the gauge iscalibrated to the movement of the gauge needle.

Gauge sending unitsGauge sending unitsGauge sending unitsGauge sending unitsGauge sending units

1111122222

22222

1. Thermistor1. Thermistor1. Thermistor1. Thermistor1. Thermistor2. V2. V2. V2. V2. Variable resistorariable resistorariable resistorariable resistorariable resistor


43

In the previous illustration, the tachometer, speedometer, fuel gauge and water temperaturegauge receive battery voltage with the ignition switch in the ON or START position. Voltage issupplied through terminals #41, #10 and #22 to the speedometer, tachometer, watertemperature and fuel gauges.

The other combination meter terminals connect to ground and gauge sensors or transmitters.For example, terminal #42 connects to the thermal transmitter to sense coolant temperature.Terminal #14 connects to the fuel tank gauge unit to sense fuel level in the gas tank.

Speedometer Operation

The speedometer receives an alternating current (AC) signal from a vehicle speed sensor. Thevehicle speed sensor is attached to the drivetrain (transaxle/transmission). It mechanicallytransmits the AC signal through terminals #24 and #30 at the combination meter (see theprevious illustration, ELTC1-46, page 36).

Speed Sensor Pinion

Speed Sensor

The AC signal is an analog signal (also called a sine wave). The voltage is measured continuouslyin one second intervals. The number of complete sine waves produced in one second is calledthe number of cycles-per-second or the number of Hertz (Hz). Hertz applies to the frequency ofany repetitive signal.

The vehicle speed sensor signals are also sent to the ECM, automatic transmission control unitand ASCD control unit by way of the speedometer.


44

MOTORS

Motors are electromagnetic devices and have many applications. You’re probably most familiarwith the starter motor. Smaller motors operate windshield wipers, electric windows, powerseats, sunroofs, power antennas, and fuel pumps.

When current is applied to a motor, it creates two magnetic fields. The field coils are constant:one is always north, the other always south. However, the magnetic field in the armatureswitches so the attraction/repulsion effect of the armature’s magnetic field will cause thearmature to spin. Repulsion of two north poles, for example, “pushes” the armature about aquarter turn. Then the attraction of a north and south pole “pulls” the armature an additionalquarter turn to maintain the momentum of the motor.

To match the motor to the operating requirements of the system, many windings of wire arewrapped around the field shoes and armature. The number of windings determines the speedand torque of the motor.

Some motors, such as window and sunroof motors, need to rotate in two directions. Changingthe direction a motor rotates involves using a switch to change the polarity from positive (+)(voltage), to negative (–) (ground) to the motor.....

TTTTTroubleshooting Tip #12:roubleshooting Tip #12:roubleshooting Tip #12:roubleshooting Tip #12:roubleshooting Tip #12:When diagnosing motor circuits, directional control of the motor is important. If one brushis direct to SOURCE or GROUND, the motor runs in one direction.

MOTORS

45

STARTING SYSTEM

TTTTTypical Automatic Typical Automatic Typical Automatic Typical Automatic Typical Automatic Transmission-Equipped Vransmission-Equipped Vransmission-Equipped Vransmission-Equipped Vransmission-Equipped Vehicle:ehicle:ehicle:ehicle:ehicle:

The starting system cranks the engine when starting. The starting system consists of the:

• starter motor

• ignition switch

• park/neutral position relay

• park/neutral position switch

• related fuse

• fusible link

• wiring and connections

For the starter to operate, a 40A fusible link to the ignition switch supplies source voltage fromthe battery at all times. With the ignition switch in the ON or START position, a 15A fuse to thepark/neutral position relay supplies source voltage.

In addition, with the ignition switch in the START position, the ignition switch supplies sourcevoltage to the park/neutral position relay. The circuit is grounded when the selector lever is ineither the P or N position. The park/neutral position relay is energized by power supplied from theignition switch, through the park/neutral position relay to the starter motor windings. When thiscircuit is complete, the starter motor plunger closes, providing a complete circuit between thebattery and the starter motor. The starter motor is grounded to the cylinder block. With sourcevoltage and ground supplied, the starter motor operates.

STARTING SYSTEM

46

Starting System: VStarting System: VStarting System: VStarting System: VStarting System: Vehicles with A/Tehicles with A/Tehicles with A/Tehicles with A/Tehicles with A/T

STARTING SYSTEM

47

TTTTTypical Manual Typical Manual Typical Manual Typical Manual Typical Manual Transmission-Equipped Vransmission-Equipped Vransmission-Equipped Vransmission-Equipped Vransmission-Equipped Vehicle:ehicle:ehicle:ehicle:ehicle:

On manual transmission-equipped models, the starting system consists of the starter motor,ignition switch, clutch interlock relay, clutch interlock switch, related fuse, fusible link, wiring andconnections. For the starter to operate, source voltage a 40A fusible link supplies at all times tothe ignition switch. With the ignition switch in the START position, source voltage is suppliedthrough the ignition switch to the clutch interlock relay.

In addition, with the ignition switch in the START position, a 10A fuse supplies source voltage tothe clutch interlock relay. While you hold the clutch pedal depressed, ground is supplied to theclutch interlock relay through the clutch interlock switch and accompanying body grounds. Theclutch interlock relay is then energized and source is supplied from the clutch interlock relay to thestarter motor windings. The starter motor plunger closes and provides a closed circuit betweenthe battery and the starter motor.

The starter motor is grounded to the cylinder block. With source and ground supplied, the startermotor operates.

Starting System Diagnosis & Repair Procedure

Note:Note:Note:Note:Note: If a starting system failure is indicated, you must complete visual inspections and voltagedrop tests before replacing the starter. Follow these steps to ensure that other possiblecauses are ruled out first.

1. Confirm starting system failure symptom by attempting to start the engine.

2. Check condition of all fuses and fusible links connected to the starting system circuit.

3. Check condition of all accessible harness connectors connected to the starting systemcircuit.

4. Ensure the vehicle has a fully charged battery that meets vehicle specifications installed.

5. Ensure engine mechanical condition is good. A vehicle that exhibits extended crankingsymptoms may cause additional strain on the starting system. This could possibly result instarter failure.

6. Test starting system using Kent-Moore J44373 Battery, Starter, Charging System tester.

7. If a starting system failure is indicated, perform voltage drop tests on the starting systembefore replacing the starter. Perform voltage drop tests while cranking the engine.

8. Compare your readings with the known good readings shown in the graphics on thefollowing pages. If your readings do not agree with these readings, check a known goodvehicle with the same engine as the one you are testing.

STARTING SYSTEM

48

Starting System: VStarting System: VStarting System: VStarting System: VStarting System: Vehicles with M/Tehicles with M/Tehicles with M/Tehicles with M/Tehicles with M/T

STARTING SYSTEM

49

CHARGING SYSTEM DESCRIPTION

The charging system provides DC voltage to operate the vehicle’s electrical systems and to keepthe battery charged. It consists of the alternator, ignition switch, charge indicator lamp in thecombination meter and related fuse, fusible link, wiring and connections.

The IC regulator controls alternator output voltage at the S terminal. For the alternator to charge,a 120A fusible link and a 10A fuse supplies power at all times to terminal S. Terminal B suppliespower to charge the battery and operate the vehicle’s electrical system. The alternator isgrounded to the engine block.

With the ignition switch in the ON or START position, a 10A fuse supplies source to thecombination meter for the charge warning lamp. Ground is supplied to the combination meterthrough terminal L of the alternator. With source and ground supplied, the charge warning lampwill illuminate. When the alternator is producing sufficient voltage with the engine running, theground is opened and the “charge” warning lamp will go off. If the charge warning lampilluminates with the engine running, a fault is indicated.

Charging System Diagnosis & Repair Procedure

Note:Note:Note:Note:Note: If a charging system failure is indicated, complete visual inspections and voltage droptests before replacing the alternator. Follow these steps to ensure that other possiblecauses are ruled out first.

1. Check the condition of all fuses and fusible links connected to the charging system circuit.

2. Check condition of all accessible harness connectors connected to the charging systemcircuit.

3. Check condition and tension of the alternator drive belt.

4. Ensure the vehicle has a fully charged battery that meets vehicle specifications installed.

5. Ensure that engine mechanical condition is good. Any vehicle that exhibits extendedcranking symptoms may cause additional strain on the charging system. This could result inalternator failure.

6. With the ignition ON, engine OFF, confirm the “Charge” lamp is ON.

Note:Note:Note:Note:Note: If the Charge lamp is not on, diagnose this problem first. The charging system will notwork if the charge lamp is not working.

7. Confirm charging system failure using Kent-Moore J44373 Battery, Starter, ChargingSystem tester.

8. Perform voltage drop tests of the charging system circuits with the engine running at aconstant 1500-RPM. Load the alternator by turning headlamps and rear window defoggerON.

CHARGING SYSTEM DESCRIPTION

50

Charging SystemCharging SystemCharging SystemCharging SystemCharging System

CHARGING SYSTEM

51

ELECTRICAL DIAGRAMS

Service literature uses two types of diagrams to help interpret and trace the wiring on vehicles:

• Schematic Diagrams

• Wiring Diagrams

Schematic Diagrams

The schematic diagram is a simplified electrical diagram of a circuit. This example of a turn signaland hazard warning lamps circuit shows all the main components of the circuit. This makes iteasy to find source, load and ground on one page. However, the diagram does not showimportant repair details such as connector numbers, wire color codes and fuse identification andlocation. For that you need a wiring diagram.

Wiring Diagrams

ELECTRICAL DIAGRAMS

52

Wiring Diagrams provide a road map of electrical circuits and contain more detail than schematicdiagrams. They show:

• Connector types and color

• Wire colors

• Wire position in the connector

• Connector numbers (for location)

• Location of wiring harness on the car

• Fuse ratings

• Accessory wiring harnesses

• Number of pin receptacles in a connector

• Splices in a circuit

• Ground locations

Wiring diagrams provide a detailed view of a system. This can help isolate individual circuits fortesting. The ability to follow and interpret electrical diagrams is essential to diagnose and repairelectrical circuit malfunctions.

Wiring diagrams contain many important abbreviations, symbols, identifiers and codes. Thefollow example describes these important features. Recognizing them and knowing what theymean will help you use wiring diagrams more effectively when diagnosing and repairing electricalmalfunctions.

TTTTTroubleshooting Tip #13:roubleshooting Tip #13:roubleshooting Tip #13:roubleshooting Tip #13:roubleshooting Tip #13:Though a wiring diagram may show only one wire in a connector, there may be more.Other wires will not appear when they are part of different, unrelated circuits.

ELECTRICAL DIAGRAMS

53

The example wiring diagram below shows:

• R/L is a Red wire with a blue stripe which connects terminal 12 of the combination switchand terminal 12S of the fuse block.

• Fuse block terminal 11S connects to both front side marker lamp assemblies.

• Fuse block terminal 10Q connects to the taillamp circuit shown on the next page of therepair manual.

Electrical wiring diagrams divide the entire electrical system into individual circuits. Thus, a typicalwiring diagram shows one circuit from battery to ground. Wiring and components that are notpart of the individual circuit are cross-referenced at connection points.

Tail lamp circuit continues on next page

ELECTRICAL DIAGRAMS

54

These wiring diagrams are easy to read and trace because the source (battery) is always at thetop of the page and the ground connections are always at the bottom of the page (as if currentflows down hill). Components, wires, switches, lamps and fuses are shown as simply aspossible. For example, a wire that is 6 feet in length on the vehicle may be shown no differentlythan one that is 6 inches long.

The General Information (GI)General Information (GI)General Information (GI)General Information (GI)General Information (GI) section in the service manual describes how to read the new stylewiring diagrams. Review the sample diagram Graphical Wiring Diagram in this section as well asthe accompanying explanations of the lines and symbols.

The Electrical (EL)Electrical (EL)Electrical (EL)Electrical (EL)Electrical (EL) section of newer service manuals contains the following types of diagnosticinformation:

• Wiring diagramsWiring diagramsWiring diagramsWiring diagramsWiring diagrams, which show the electrical current path when the circuit is operatingproperly. It is essential to understand how a circuit should operate before attempting todiagnose a malfunction.

• System descriptionsSystem descriptionsSystem descriptionsSystem descriptionsSystem descriptions, which describe how current flows through the system from thesource to the ground.

• Component part locationsComponent part locationsComponent part locationsComponent part locationsComponent part locations, which show a picture of where the component is actuallylocated on the vehicle.

• Harness layout and connector locationsHarness layout and connector locationsHarness layout and connector locationsHarness layout and connector locationsHarness layout and connector locations, which are found toward the back of the EL EL EL EL ELsection.

• Diagnostic proceduresDiagnostic proceduresDiagnostic proceduresDiagnostic proceduresDiagnostic procedures, which provide a step by step diagnostic procedure based on themalfunction symptom.

Example:To review how the Meter and Gauge circuit operates, turn to the Meters and Gauges SystemDescription in the EL EL EL EL EL section of the service manual. Read the System Description and analyzethe wiring diagram(s) to get a basic understanding of how the circuits operate. After learninghow the circuit should operate, perform basic visual inspections and checks for available voltageand ground. This is important because many diagnostic procedures assume you have checkedfor voltage and ground before performing further diagnostic procedures.

ELECTRICAL DIAGRAMS

55ELECTRICAL DIAGRAMS

Connector Symbols in Electrical Diagrams

In order to diagnose and repair electrical malfunctions, you must understand how to read andinterpret wiring diagrams.

The wiring diagram includes all the details of how the circuit is actually wired on the vehicle. Thewiring diagram includes all connectors, wire colors, fuse locations and connector referencelocations.

In this vehicle wiring diagram the horn relay connects to the engine harness at E37. To furtherisolate the location of this connector, refer to the Harness Layout Diagram in the EL section ofthe service manual.

Horn Relay andConnector E37

Typical switch details

Typicalgroundsymbol

56 ELECTRICAL DIAGRAMS

Since electrical diagrams include a lot of information on a single page, accurate tracing of a singlecircuit is not always easy. Remember these important points when you use the diagrams:

• The two halves of a connector fold like a book.

• Wires sometimes change colors from one side of awire connector to the other side.

• All connector symbols in wiring diagrams are viewedfrom the terminal side, unless otherwise noted.

• Only the wires that are part of the circuit are shownin the connector.

• If the plastic connector is female, the terminalsinside are male, and vice versa.

NoteNoteNoteNoteNote: Though a wiring diagram may show only one wire in a connector, there may be more.Other wires will not be shown when they are part of different, unrelated circuits.

Symbol

As there are six cavities, theconnector has up to six terminals

Black print shows that it houses amale terminal (metal part not plastic)

A chamfered corner shows thatit is a pin-type terminal

A right-angled corner meansthat it is a flat or spadeterminal

Since it is white here, it is a femaleterminal (metal part)

There are eight cavities, so theconnector has up to eight spadeterminals

Connector with pin terminals

Connector with spade terminals

57ELECTRICAL DIAGRAMS

• Connector guides for male terminals have a black mark on the connector symbol.Connector guides for female terminals have a white or hollow area on the connectorsymbol.

Refer to a component’s wiring diagram to determine the number of wires, type of connector andwhether it is male or female.

NoteNoteNoteNoteNote: An “X” in a wiring diagram wire connector means there is no terminal in that connectorcavity.

Guide

Connector symbol Connector

Female TFemale TFemale TFemale TFemale Terminalerminalerminalerminalerminal

Male TMale TMale TMale TMale Terminalerminalerminalerminalerminal

Connector symbol Connector

GuideSymbol Actual connector

Number of cavities Number of terminals available

Black print Male terminal

White print Female terminal

Chamfered corner Pin-type connector (bullet)

Right-angled corner Spade terminal

X

no terminal

Connector symbolConnector symbolConnector symbolConnector symbolConnector symbol

58

Connector Direction Marks

A direction mark symbol is used to differentiate between the harness side of the connector andthe terminal side of the connector. These marks represent the side of the connector which shouldbe tested.

View from harness side (HS)View from terminal side (TS)

All connector symbols shown from the terminal side are enclosed by a single line, and connectorsymbols shown from the harness side are enclosed by double lines.

Connector symbols

Single line Double line

View from terminal sideView from terminal sideView from terminal sideView from terminal sideView from terminal sideView from harness sideView from harness sideView from harness sideView from harness sideView from harness side

Each connector symbol also includes a guide for the connectors.

If the guide is not filled in, the wire terminals are female.

If the guide is black, the wire terminals are male.

In addition, the troubleshooting guide flow charts use symbols to indicate whether a test shouldbe performed with the connector connected or disconnected, as well as many other testingconditions that must be met.

ELECTRICAL DIAGRAMS

59

Wire Color CodeWire Color CodeWire Color CodeWire Color CodeWire Color Code

A standard color code has a one or two letter code (e.g. “R, W, B or BR”). If a wire has a twoletter code separated by a slash (e.g. “R/W” or “G/Y”), the first letter represents the standardcolor and the second letter represents the supplementary (stripe) color. The standard color for“grounding circuits” is black. Wires connected to some components may also be black. Blackwires are not always ground wires.

If the wire insulation color is striped, the base color is given first, followed by the stripe color.Example: L/W = Blue with White Stripe

Wire GaugeWire GaugeWire GaugeWire GaugeWire Gauge

Wire gauge describes the diameter of wire conductors. As the wire gauge number gets larger,wire diameter gets smaller. Large gauge wire has greater current-carrying capacity. For example,a 10 gauge wire conductor is thicker than a 14 gauge wire and can carry up to 24 amps while the14 gauge wire can carry a maximum of 14 amps.

10 gauge wire compared with 18 gauge wire10 gauge wire compared with 18 gauge wire10 gauge wire compared with 18 gauge wire10 gauge wire compared with 18 gauge wire10 gauge wire compared with 18 gauge wire

InsulationConductor

ELECTRICAL DIAGRAMS

trahCedoCroloCeriW

B = kcalB RB = nworB

W = etihW OroRO = egnarO

R = deR P = kniP

G = neerG RGroYG = yarG

L = eulB VroUP = elpruP

Y = wolleY BS = eulBykS

GL = neerGthgiL HC = nworBkraD

GD = neerGkraD

60

Wiring Repairs

Nissan and Infiniti provide wiring harnesses and most electricalcomponents as repair parts. An electrical terminal kit with anassortment of electrical terminals and terminal remover tools isavailable for minor wiring harness repairs. When working on wiringharnesses, always use the appropriate terminal removal tool. Usingthe proper tool reduces damage to the wire terminals andconnectors. Solder terminals and cover exposed wires withshrink wrap.

NoteNoteNoteNoteNote: When repairing electrical wiring, always use the correct wiresize and avoid using solderless terminals.

Wire Connectors

Harness connectors are designed tostay tightly connected. To separatethese connectors, push or lift aspecial locking section of theconnector. Never pull the wireharness when separatingconnectors.

In spite of the locking design,connectors sometimes becomeloose or disconnected. Attempt topull the two connector halves apartto verify they are making goodcontact. When separating aconnector, be sure the waterproofseal is in place when you reconnectit. Look for signs of corrosion ordiscoloration that can causeincreased resistance, which leads tounwanted voltage drop.

Disconnecting, inspecting, and reconnecting wire connectors in a non-functioning circuit willoften return the circuit to operation. The act of separating and reconnecting the connector cleansand reseats the connector terminals.

Connection Repair Kit

Terminal retainer

waterproofseal

PushPushLift

PushPush

Push(for combination meter)

(for relay)

PushPush

Terminal retainer

ELECTRICAL DIAGRAMS

61

Trouble Diagnosis Charts

Troubleshooting guides for many systems are also included in the ELELELELEL section of the servicemanual. They are a valuable source of information to solve circuit malfunctions. The chart isdivided into three columns to help pinpoint the cause of the circuit malfunction. The circuit wiringdiagram accompanies the Trouble Diagnosis Chart. Symbols are used to identify the tasks to beperformed.

NoteNoteNoteNoteNote: Follow the chart completely. Do not skip around. Perform each test before going on to thenext.

Be sure you know what each test is telling you. You should have a good idea what part ofthe circuit is being checked and the results a good component will give.

Harness Connector I.D.

Note terminallocation inmale/femaleconnectors

Circuit Wiring DiagramCircuit Wiring DiagramCircuit Wiring DiagramCircuit Wiring DiagramCircuit Wiring Diagram Circuit Diagnostic FlowchartCircuit Diagnostic FlowchartCircuit Diagnostic FlowchartCircuit Diagnostic FlowchartCircuit Diagnostic Flowchart

ELECTRICAL DIAGRAMS

62

Trouble Diagnosis Charts contain symbols which are identified by a number. A description ofeach symbol and number follows.

a An _______________ is used to check continuity.

b The _________________ is “OFF”.

c The __________________ is disconnected.

d One lead of the ohmmeter is connected to _____________.

e E14 is the _____________________.

f _________ terminals inside connector.

g Perform the test at _______________ #33.

h Perform the test on the _______________ of connector E14.

i The wire connector is viewed and ____________ from the harness side.

NoteNoteNoteNoteNote: All test conditions must be met if you want accurate results.

AAAAA

E147

5

4

6

1

Disconnect33

3

2

8

9

ELECTRICAL DIAGRAMS

ohmmeterohmmeterohmmeterohmmeterohmmeter

ignition switchignition switchignition switchignition switchignition switch

wire connectorwire connectorwire connectorwire connectorwire connector

groundgroundgroundgroundground

connector numberconnector numberconnector numberconnector numberconnector number

Male Male Male Male Male

terminalterminalterminalterminalterminal

harness sideharness sideharness sideharness sideharness side

testedtestedtestedtestedtested

63

Key to Electrical SymbolsKey to Electrical SymbolsKey to Electrical SymbolsKey to Electrical SymbolsKey to Electrical Symbols

ELECTRICAL DIAGRAMS

64

Harness Layout DiagramsHarness Layout DiagramsHarness Layout DiagramsHarness Layout DiagramsHarness Layout Diagrams

Harness Layout diagrams describe the locations of all connectors of a specific harness as theyappear on the vehicle. In addition, these diagrams show ground locations and some of the majorcomponents that connect to the harness. This layout for the taillight harness shows the locationof each connector. Verify the correctness of the connector location by matching wire colors andnumber of wires prior to performing tests.

Locate harness connectorsusing layout diagrams

TTTTTaillight Wiring Diagramaillight Wiring Diagramaillight Wiring Diagramaillight Wiring Diagramaillight Wiring Diagram

Connector numbers

Harness Layout Diagram:Harness Layout Diagram:Harness Layout Diagram:Harness Layout Diagram:Harness Layout Diagram:TTTTTail Harnessail Harnessail Harnessail Harnessail Harness

ELECTRICAL DIAGRAMS

65

Location of Electrical Units

The ELELELELEL section of the service manual shows the location of major electrical components in thesegment labeled Location of Electrical Units. Both under-hood and interior locations aredescribed. The location of components description is approximate and may change dependingon installed accessories and available options.

LLLLLOCAOCAOCAOCAOCATION OF ELECTRICAL UNITSTION OF ELECTRICAL UNITSTION OF ELECTRICAL UNITSTION OF ELECTRICAL UNITSTION OF ELECTRICAL UNITS

Passenger Compartment

TTTTTroubleshooting Tip #14:roubleshooting Tip #14:roubleshooting Tip #14:roubleshooting Tip #14:roubleshooting Tip #14:After tracing a circuit with the wiring diagram, use the Location of Electrical Units sectionto locate test points that are easy to find and will help isolate the problem.

ELECTRICAL DIAGRAMS

66

Foldout Circuit Diagrams

The foldout pages at the back of some service manuals contain valuable information fordiagnosing circuit malfunctions. Information contained in these foldout pages varies dependingon the year of the service manual. Service manuals produced before the 1994-95 Model Yearcontain different electrical information than manuals produced after those years. There are twotypes of foldout pages used in service manuals:

1. Foldout Circuit Diagrams used in 1994 andolder service manuals.

Service manuals produced before 1994 usefoldout pages that contain circuit diagrams of theentire vehicle. These foldout circuit diagramsseparate the electrical system into three levels.Each level has power at the top, the circuit load inthe middle and ground at the bottom. Analyzing acircuit in this format helps to eliminate the clutter ofwires, components and connectors. Use thefoldout circuit diagram to determine whatcomponents of other circuits interconnect with thecircuit you’re tracing.

ELECTRICAL DIAGRAMS

67

2. Foldout Circuit Diagrams used in 1995 and later service manuals.

1995 and newer service manuals have foldout pages that contain detailed connectorand terminal location information for these items:

• Super Multiple Junction (SMJ)

• Hybrid Electrical Connector (HEC)

• Fuse and Fusible Link Box and the Junction Box.

Examine the following sample foldout page. Notice how the reference area on the starting systemwiring diagram page is linked to the SMJ terminal arrangement foldout page. This is helpful whentrying to locate a terminal for testing.

ELECTRICAL DIAGRAMS

68

Power Supply Routing Schematic

This is a schematic diagram that identifies all the system fuses and the different circuits that arepowered by each fuse. Use this chart to identify and locate the available voltage for a circuit.

Horn relay-2

Cooling fan relay-2

Cooling fan relay-3

Theft warning lamp relay

Theft warning relay

Front fog lamp relay

Multi-Remote control relay

A/C relay

Clutch interlock relay (M/T models)

Inhibitor relay (A/T models)

Horn relay

Cooling fan relay-1

ELECTRICAL DIAGRAMS

69

Ground Distribution Chart

These charts identify all the electrical system ground connections, connector numbers and wiringdiagrams for each circuit. When a system ground is suspected as being faulty, this chart canidentify the ground connector and the various circuits shared by common grounds.

Ground connection location

Circuit description

Load connector number

Circuit Identificationin service manual

Answer the following questions in regard to the __________________ service manual:

1. What page in the service manual page contains the brake fluid level circuit? ________

2. Where in the vehicle is the ground connection (E13/E25) for this circuit?

_______________________

3. What page in the service manual page contains the Harness Layout chart for this circuit?___ ______

4. What are the coordinates on the Harness Layout that identify the location of the Brake FluidLevel Switch connector (E1)? __________

ELECTRICAL DIAGRAMS

ELELELELEL-102-102-102-102-102

Behind left front headlightBehind left front headlightBehind left front headlightBehind left front headlightBehind left front headlight

ELELELELEL-236-236-236-236-236

E-2E-2E-2E-2E-2

1997 200SX/Sentra1997 200SX/Sentra1997 200SX/Sentra1997 200SX/Sentra1997 200SX/Sentra

70

Using the Service Manual to Research Related Information

Now that you are familiar with the layout of the electrical (EL) section of the service manual andlearned how to interpret information, imagine you’re in a situation where you need to thoroughlyresearch a circuit. You might look for related circuit information like component locations, powerfeeds, SMJ connectors, electrical units, joint connectors or ground locations. The followingpages are similar to how you might research them in a diagnostic situation. By gathering thesepages, you should be able to better understand how various components are related.

The following pages are related to the horn circuit on a 2001 model Maxima. When conductingresearch of your own, you might find it useful to have pages such as these to help you diagnosea particular circuit fault.

Use this as a reference until you feel comfortable locating the different sections of the manual onyour own.

ELECTRICAL DIAGRAMS

71

HORN

Engine harness

See engine room harness(ground distribution)

ELECTRICAL DIAGRAMS

72

VEHICLE SECURITY (THEFT WARNING) SYSTEM

ELECTRICAL DIAGRAMS

73

POWER SUPPLY ROUTING

Hor

n ci

rcui

t (po

wer

sup

ply)

fuse

s

ELECTRICAL DIAGRAMS

74


ELECTRICAL DIAGRAMS

75


ELECTRICAL DIAGRAMS

76

HARNESS LAYOUT

Outline

ELECTRICAL DIAGRAMS

77

HARNESS LAYOUT

How to Read Harness Layout

ELECTRICAL DIAGRAMS

78

HARNESS LAYOUT

Engine Room Harness

ELECTRICAL DIAGRAMS

79

HARNESS LAYOUT

ELECTRICAL DIAGRAMS

80

GROUND

Engine Room Harness

ELECTRICAL DIAGRAMS

81

GROUND

ELECTRICAL DIAGRAMS

82

ELECTRICAL UNITS LOCATION

Engine Compartment

ELECTRICAL DIAGRAMS

83


Passenger Compartment

ELECTRICAL DIAGRAMS

84


ELECTRICAL DIAGRAMS

85


ELECTRICAL DIAGRAMS

86

ELECTRONICALLY CONTROLLED CIRCUITS

The last category of vehicle circuits found on vehicles is called electronically controlled circuits.These circuits use an Electronic Control Unit (ECU) with various inputs and outputs. TheseECUs are sometimes called amplifier or timer circuits. For example, an A/C Auto Amp controls airconditioning compressor operation; an automatic temperature control (ATC) head is called anauto amplifier; a door lock timer controls power door lock operation.

Operation

Electronic circuits are unique because an ECU uses internal logic, circuitry and memory tocontrol circuit operation. Relay and switch circuits do not have these capabilities. Electronicallycontrolled circuits require:

• Input - Sensors provide electrical signals to the ECU.

• Logic - Processing of input signals to determine the output signal.

• Output - Signal provided by the ECU that controls operation of the load.

Symptoms

ECU-controlled load circuits can have these malfunction symptoms:

• The load does not operate or ...

• The load operates all the time, or ...

• The load operates at the wrong time

These symptoms can be caused by missing or incorrect sensor input signals, the logic inside theECU, or the output circuit.

TTTTTroubleshooting Tip #15:roubleshooting Tip #15:roubleshooting Tip #15:roubleshooting Tip #15:roubleshooting Tip #15:Correct output signals from electronically-controlled circuits require correct input signals.


87

ECU Inputs

Input sensors for electronically controlled circuits report information to the ECU. The ECU usesinput information to determine how to control output loads. There are two types of ECU inputs:

• Digital signals

• Analog signals

Digital signals are ON-OFF voltage pulses, typically 2.5 or 5 volts. An example of a digital inputdevice is the camshaft position sensor which creates a camshaft position signal.

A typical digital signal looks like this:

Analog signals are produced by sensors that mechanically change resistance to deliver variablevoltage signals within a fixed operating range. These components are called variable resistors orpotentiometers. On vehicles, analog signals can come from:

• Throttle position sensor

• Fuel tank gauge units

• Vehicle speed sensor

A typical analog signal looks like this:

While potentiometers change resistance mechanically, electronic components also providevariable analog inputs to ECUs. These electronic, variable resistors are called thermistors orthermal transmitters (see page 29). Thermistors change their internal resistance based ontemperature changes. Examples of thermistors include:

• Engine coolant temperature sensors

• Intake air temperature sensors

• EGR temperature sensor

• Fuel tank temperature sensor

• Ambient temperature sensor

Thermistor


88

Electronic Control Units (ECUs)

The ECU in a circuit compares the input voltage it receives with data stored in its memory. Thistype of analysis by the ECU results in an output from the ECU. As we said, ECU system outputsrely on the inputs for the system to operate correctly.

NoteNoteNoteNoteNote: Correct output from electronically controlled circuits requires correct input.

To process voltage inputs and to produce outputs, ECUs have two operating memories: ReadOnly Memory (ROM) and Random Access Memory (RAM). ROM and RAM work together toevaluate inputs and deliver the appropriate output signal.

ROM is permanently programmed with the operatingdata necessary to control output. For example, ROMin a timer control unit stores data to control thelength of time the interior lights stay on after thedoors have closed. The ROM program is “burned”into the electronic chip in the ECU and is notdependent on a power supply to maintain programdata. Since one input sensor can affect severaloutputs, the ROM program is very complex. ROMcan take into account all the various combinations ofinputs to make the correct output decisions.

Unlike permanently programmed ROM, RAM cancreate and store new data in addition to readingpreviously stored information. An example of RAM isthe ECU built into a digital car radio for the stationselection memory switches. Because RAM isdynamic, it requires an uninterrupted power supply to maintain its stored values. If battery poweris disconnected from the radio or if the battery goes dead, all RAM is lost and the stationselections must be reprogrammed.

NoteNoteNoteNoteNote: When servicing a vehicle with an electronic radio, write down the radio station presetsbefore you disconnect the battery.


89

ECU Outputs

There are three types of outputs from electronically-controlled circuits:

• Reference (typically 5 volts) constantly ON or OFF

• Ground constantly ON or OFF

• Pulsed reference or ground

Switched ECU voltage or ground can bemeasured using a voltmeter or oscilloscope.Voltmeter readings of pulse only indicate theaverage voltage present. On the other hand, anoscilloscope displays exact voltages as shownin the illustration at right.

To diagnose the operation of ECU circuits, measurements must also include:

• Frequency (Hz)

• Duty cycle (% ON)

• Pulse width (Duration ON)

Cycle

A complete cycle occurs when voltage is pulsed high, then low, then high again. It is said to bemeasured from start-to-finish (digital) or peak-to-peak (analog). See the following illustrations.

Frequency

A pulse occurs when current is switched ON, then OFF. Each pulse or cycle starts when thecurrent switches ON and ends when it switches ON again. The frequency of the pulse isdetermined by how often the current cycles ON and OFF per second. The unit of measurementfor frequency is Hertz, often abbreviated Hz. Frequency merely expresses the number of cyclesper second (cps) the pulsing occurs.

Cycle

Cycle

(Digital Signal)(Analog Signal)

Voltage high (circuit OFF)OFF

ON Voltage “pulled low” (circuit ON)(Ground switched ON)


90

The operation of a flywheel sensor is an example of how frequency is used to meet the operatingrequirements of an engine. As engine speed changes, the frequency of the sensor input changes.The ECM uses this sensor input to monitor engine misfire.

A vehicle speed sensor is a good example of how frequency is used as an input to the ECM.

RotatingRotatingRotatingRotatingRotatingMagnetMagnetMagnetMagnetMagnetSpeedSpeedSpeedSpeedSpeedSensorSensorSensorSensorSensor

DashboardDashboardDashboardDashboardDashboardControlControlControlControlControl

UnitUnitUnitUnitUnitECMECMECMECMECM

RotatingRotatingRotatingRotatingRotatingMagnetMagnetMagnetMagnetMagnetSpeedSpeedSpeedSpeedSpeedSensorSensorSensorSensorSensor

DashboardDashboardDashboardDashboardDashboardControlControlControlControlControl

UnitUnitUnitUnitUnitECMECMECMECMECM

Signal at 40 mphSignal at 40 mphSignal at 40 mphSignal at 40 mphSignal at 40 mph

Signal at 15 mphSignal at 15 mphSignal at 15 mphSignal at 15 mphSignal at 15 mph

Duty Cycle %

Frequency alone however, is not sufficient to describe pulsed signals. In some cases frequencyremains constant, but the length of ON time changes. Duty cycle is measured as percentage. Forexample, a duty cycle of 50% means that the % of ON time and OFF time is the same. If the ONtime is 25% of the cycle, the duty cycle is 25%.

0V0V0V0V0V

5V5V5V5V5V 5V5V5V5V5V

0V0V0V0V0V

1Hz 50% Duty1Hz 50% Duty1Hz 50% Duty1Hz 50% Duty1Hz 50% Duty 1Hz 25% Duty1Hz 25% Duty1Hz 25% Duty1Hz 25% Duty1Hz 25% DutyVVVVVoltage high,oltage high,oltage high,oltage high,oltage high,output deviceoutput deviceoutput deviceoutput deviceoutput device

OFFOFFOFFOFFOFF

VVVVVoltage lowoltage lowoltage lowoltage lowoltage low,,,,,output deviceoutput deviceoutput deviceoutput deviceoutput device

ONONONONON

Éxamples:

• Idle control solenoids

• Shift solenoids A & B found on electronically-controlled automatic transmissions

• Lock-up torque converter solenoids

• Automatic transmission line pressure solenoids


91

Measuring Duty Cycle

Electronic test equipment reads and measures the duty cycle and displays an average that is theresult of readings over a long period of time. Duty cycles are used to control actuators such asthe auxiliary air control (AAC) valve of the ECCS system. The position of the AAC valve controlsengine idle speed and is determined by the average amount of ON time in relation to OFF time.

Pulse Duration (Time ON)

Pulse duration is similar to duty cycle. However, while duty cycle is a percentage of ON time inrelation to OFF time of the signal, pulse duration is more accurate. Rather than take an averagereading over a long period of time, pulse duration is a measurement of the length of time thesignal is ON, usually in milliseconds (thousandths of a second). Changes in pulse duration affectthe operation of some components. When the ECCS control unit determines the enginerequires more fuel, fuel injector pulse duration increases allowing the injector to stay open longer.The ECM makes constant adjustment to fuel injector ON-time meeting the engine's ever-changing fuel volume needs based on input from the camshaft position sensor (rpm). Or, simplystated, the ECM changes pulse duration (injector ON-time) by increasing or decreasing theamount of fuel delivered to the combustion chamber.

To review:

• Frequency is the number of cycles per second.

• Duty cycle is the percent (%) of time an output is ON in a cycle.

• Pulse width is the length of time a signal is ON, usually measured in milliseconds (msec).

For electronically controlled circuits to operate, inputs from sensors are processed by the ECUand outputs sent to actuator circuits.

The ECU is the processing center for these signals. However, if an ECU output load isinoperative always check the ECU inputs. As with all computer controlled circuits, the acronymGIGO is important to remember: Garbage In, Garbage out.


92

Depending on the type of signal, ECU inputs and outputs can be measured using:

• A Duty Cycle Meter

• A Pulse Duration Meter

• An Oscilloscope

• A Multimeter

• A Logic Probe

• CONSULT (Nissan/Infiniti Scan Tool)

When checking an output load in an ECU controlled circuit, supply the missing link to verifyoutput circuit operation. Remember the circuit requirements of source, load and ground. Duringdiagnosis, be careful because the loads in some ECU-controlled circuits use dropping resistors.Never bypass one of these resistors to operate such circuits or wiring could overheat due tohigher current flow.

Fill in the blanks with the correct answer:

• A __________is an event that includes voltages changes from start-to-start, or peak-to-peak.

• The number of times a cycle repeats in a second is measured in ___________.

• The percentage of ON time during a cycle is expressed as ____________.

• The length of time a pulsed signal is ON during a cycle is referred to as__________________.

• An example of a frequency input is _______________________.

• An example of a duty cycle output circuit is ____________________.

• An example of a pulse duration output circuit is __________________.

TTTTTroubleshooting Tip #16:roubleshooting Tip #16:roubleshooting Tip #16:roubleshooting Tip #16:roubleshooting Tip #16:Electronically-Controlled Units: When servicing a vehicle with an electronic radio, writedown the radio stations before you disconnect the battery.


93

ELECTRICAL DIAGNOSIS

Diagnosing electrical malfunctions, like any other vehicle system, involves investigating the causeof the problem and reaching a conclusion based on your investigation. Accurate diagnosisrequires understanding how the specific system functions, then evaluating whether it functions asdesigned. Basic diagnosis involves the following steps:

1. Verify the complaint ............. Apply knowledge and use reference materials to findpossible causes

2. Isolate .................................. Inspect and/or test for the possible cause in a logical order

3. Repair .................................. Diagnosis conclusion

4. Recheck .............................. Make sure the customer complaint is corrected

Fuel tank gauge doesn’t work

Inspect and diagnose, then notify customer.

Neal Barnes


94

Preliminary Diagnosis Tips:

Step 1: For unfamiliar circuits, start with the schematic diagram. This provides an overview ofthe circuit. The schematic diagram shows circuit components and how they areconnected. Always locate the circuit load first, then trace the wires back to the batteryand ground, if necessary. Check fuses and fusible links protecting the circuit inquestion.

Step 2: Use the wiring diagram for a complete picture of the circuit. The wiring diagram is thebest source to logically trace the circuit. It includes information such as wire colors,connector numbers and relay box layout. Use your knowledge of source, load andground along with the wiring diagram to help isolate the circuit for testing.

Step 3: The Harness Layout section of the service manual describes specific harness andconnector locations on the vehicle. The harness layout diagram will help you find theexact locations on the vehicle to perform your diagnosis.

Step 4: Finally, locate the actual components and the most accessible test points by using theLocation of Electrical Units section of the service manual.

On-Car Troubleshooting Tips:

• Always check the source voltage (at the battery) before testing circuit voltage.

• Visually inspect the battery connections for looseness or corrosion.

• Clean and tighten battery cables as necessary.

• Check available voltage at the load and compare it to the source voltage. If it is not thesame or nearly the same, there is an abnormal voltage drop between the battery and theload. Look for poor connections, frayed wires, etc.

• Check tightness and the condition of ground connections.

• Simulate the conditions of the problem.


95

Diagnosing Malfunctions in Circuits with Fuses or Fusible Links

Isolate malfunctions in circuits protected by fuses or fusible links by following these steps:

• Locate the wiring diagram for the circuit that has the failed (melted) fuse or fusible link.

• Make a note of all loads that operate on that circuit. There may be multiple loads protectedby a single fuse or fusible link.

• Disconnect the circuit loads one at a time to isolatewhich circuit load is causing the fuse to fail. You mayhave to install a new fuse to check each individualcircuit. For more efficient testing, temporarily replacethe fuse or fusible link with a circuit breaker that willreset by itself.

• If the fuse or fusible link still fails after all circuit loadsare disconnected, you may have to separate theharness to locate the malfunction.

NoteNoteNoteNoteNote: Always check for pinched wires in areas where work has recently been performedresulting from body repairs.

When diagnosing faults in circuits that use fuses and fusible links:

• Verify the contact between the fuse and fuse holder is clean and tight. Poor contactincreases circuit resistance. The excessive heat caused by the poor connection mayeventually cause the fuse to melt.

• Always use a fuse with the proper rating. If a fuse with a higher rating is used, the fuse willnot fail (melt) as designed. This could result in burned wiring or insulation.

• A bad fuse or fusible link cannot always be detected from the outside. Always use reliabletest equipment to check for open circuits.

• Be careful when removing a bad fusible link. When a fusible link melts, it becomes very hot.This heat can burn you or damage nearby wiring.


96

Connecting a meter to a connector terminal candamage it if the tester probe enlarges the opening.Use a T-pin designed for meter connections. Probe itfrom the wire harness side of the connector. Inspectterminals for damage from previous probing.

NoteNoteNoteNoteNote: T-pins are available in different sizes at localhobby stores.

Connector TConnector TConnector TConnector TConnector Terminal Malfunctionserminal Malfunctionserminal Malfunctionserminal Malfunctionserminal Malfunctions

Shake gently

Bend gently

Tap gentlyVibration TVibration TVibration TVibration TVibration Testsestsestsestsests

Connector

“T” pinAlligator clip DMMDMMDMMDMMDMM


97

Available Voltage and Voltage Drop Tests

The following illustrations describe two methods of diagnosing a circuit using a voltmeter. Usethe available voltage method to determine if source voltage is available to the load.

Measuring Available VMeasuring Available VMeasuring Available VMeasuring Available VMeasuring Available Voltageoltageoltageoltageoltage1. Connect the voltmeter across the

connector or part of the circuit you wantto check. The voltmeter + lead shouldbe closer to the battery and the – leadcloser to ground.

2. Operate the circuit.

3. The voltmeter will indicate how manyvolts are availalbe in that part of thecircuit.

In this circuit, the availablevoltage to the load is only 7.9volts due to excessive resistance.

Use voltage drop tests to find components or circuit branches which have excessive resistance.

0V (OK) 0.1V (OK) 7.9V (dim bulb)

0V (OK)

4V

12V

V V V

V

V

V

Switch

Connectionwith highresistance

Battery Excessive Vdrop

Measure VMeasure VMeasure VMeasure VMeasure Voltage Drop – Step by Stepoltage Drop – Step by Stepoltage Drop – Step by Stepoltage Drop – Step by Stepoltage Drop – Step by Step

1. Connect thevoltmeter as shown,starting at thebattery, then workalong the circuit.

2. An unusually largevoltage dropindicates acomponent or wireneeds repair. Thepoor connection inthe illustration showsa 4 volt drop.

In this circuit, excessivecircuit resistance hasdropped the availablevoltage by 4 volts.

NoteNoteNoteNoteNote: Each connection can (potentially) be the source of an “unwanted” or excessivevoltage drop. Normal voltage drop at each connection should be 0.1 volt or less.


98

Testing for Opens in a Circuit

Before diagnosing a system, draw a rough sketch of the system. This helps simplify the systemand reinforces your working knowledge of the system.

Available Voltage and Continuity Tests

Another method to pinpoint the cause of a circuit malfunction is to first use the voltmeter tomeasure available voltage throughout the circuit. When no voltage is found where there shouldbe voltage, switch the source OFF and open switches to isolate the suspected circuit. Use themultimeter in the ohmmeter mode to measure the continuity between test points. The aboveillustration shows two opens at A and B. Note how the ohmmeter is connected to each part ofthe suspected circuit to isolate the area causing the open circuit.

Diagnose for Open Circuit:Diagnose for Open Circuit:Diagnose for Open Circuit:Diagnose for Open Circuit:Diagnose for Open Circuit: Ignition OFF when testing resistance (Ω).Ignition ON for voltage testing.


99

Testing for Shorts in a Circuit

Diagnose for Short CircuitDiagnose for Short CircuitDiagnose for Short CircuitDiagnose for Short CircuitDiagnose for Short Circuit

Resistance Check Method

1. Disconnect the battery negative cable and remove the blown fuse.

2. Disconnect all loads powered through the fuse (SW1 open, relay disconnected and solenoid disconnected).

3. Connect one ohmmeter probe onto the load side of the fuse terminal. Connect the other probe to a knowngood ground.

4. With SW1 open, check for continuity (complete circuit).Continuity: The short is between the fuse terminal and SW1 (Point A)No Continuity: The short is further down the circuit (after SW1)

5. Close SW1 and disconnect the relay. Connect the ohmmeter probes on the load side of the fuse terminaland a known good ground, then check for continuity.Continuity: The short is between SW1 and the relay (Point B)No Continuity: The short is further down the circuit (after the relay)

6. Close SW1, then connect a jumper wire onto the relay contacts. Connect probes at the load side of thefuse terminal and a known good ground, then check for continuity.Continuity: The short is between the relay and the solenoid (Point C)No Continuity: Check the solenoid, then retrace your steps

Voltage Check Method

1. Remove the blown fuse and disconnect all loads (Open SW1, disconnect relay and solenoid) poweredthrough the fuse.

2. Turn the ignition switch to the ON or START position. Verify battery voltage at the B+ side of the fuseterminal (DMM leads to B+ terminal of fuse block and known good ground).

3. With SW1 open, check for voltage.Voltage: The short is between the fuse block and SW1 (Point A)No Voltage: The short is further down the circuit (after SW1)

4. With SW1 closed, relay disconnected and the DMM leads across both fuse terminals, check for voltage.Voltage: The short is between SW1 and the relay (Point B)No Voltage: The short is further down the circuit (after the relay)

5. With SW1 closed, jump the relay with a test lead, solenoid disconnected, then check for voltage.Voltage: The short is down the circuit of the relay or between the relay and the disconnected

solenoid (Point C).No Voltage: Retrace steps and check power to the fuse block.


100

Ground Inspection

Ground connections are very important for the proper operation of electrical and electroniccontrols. Ground connections are often exposed to moisture, dirt and other corrosive elements.This corrosion (rust) can become an unwanted circuit resistance and prevent the circuit fromoperating properly or at all. Loose connections also create excessive circuit resistance.

Ground InspectionGround InspectionGround InspectionGround InspectionGround Inspection

Remove bolt (screw) Inspect mating surfaces fortarnish, dirt, rust, etc. Clean asrequired to assure goodcontact

Diagnostic Tips for Relays

When diagnosing faults on relay-controlled circuits:

• Listen to or feel the relay click

• If no click is heard or felt, remove the relay andconnect a fused jumper as shown in theillustration at right:

- If the load now works,you have learned that theload and ground are good.

- If the load does not work and system voltage isavailable to the relay, look for circuitmalfunctions on the load side of the relay circuit.

NoteNoteNoteNoteNote: Never jump the terminals for the coil control circuit (pins #1 and #2) because higher thannormal current can damage the wiring of the control circuit.

Jumping across these terminals will blow the fuse for this circuit or even damage the ECUthat controls the circuit.


101

One Make Relay (1M)

Relay TRelay TRelay TRelay TRelay Typeypeypeypeype

Control circuit terminal nos.

#______ and #______

Contact circuit terminal nos.

#______ and #______

ColorColorColorColorColor(Appl)(Appl)(Appl)(Appl)(Appl) Relay SymbolsRelay SymbolsRelay SymbolsRelay SymbolsRelay Symbols

Blue orBlue orBlue orBlue orBlue orYYYYYellowellowellowellowellow

(All Models)

One Make Relay (1M)


#______ and #______


#______ and #______

Blue orBlue orBlue orBlue orBlue orGreenGreenGreenGreenGreen

(‘95 & older)

Two Make Relay (2M)


#______ and #______


#______ and #______

#______ and #______

BrownBrownBrownBrownBrown(All Models)

One Make Relay (1M)


#______ and #______


#______ and #______

Blue, Gray, orBlue, Gray, orBlue, Gray, orBlue, Gray, orBlue, Gray, orYYYYYellowellowellowellowellow

(All Models)


102

One Transfer Relay (1T)

Relay TRelay TRelay TRelay TRelay Typeypeypeypeype



ColorColorColorColorColor(Appl)(Appl)(Appl)(Appl)(Appl) Relay SymbolsRelay SymbolsRelay SymbolsRelay SymbolsRelay Symbols

BlackBlackBlackBlackBlack(‘95 & newer,some circuits)

One Transfer Relay (1T)



BlackBlackBlackBlackBlack(‘95 & older)

#______ and #______

#______ and #______

One Make-One BreakRelay (1M-1B)



GrayGrayGrayGrayGray(All models)

#______ and #______

Not energized: #___ & #___

Energized: #___ & #___





NoteNoteNoteNoteNote: A relay removed from a circuit can be tested in the following manner:

1. Connect voltage to terminal #1.2. Connect terminal #2 to a good ground. Listen for a click.3. Use a multimeter to check continuity between the output terminals.4. If there is continuity, the relay is working. If not, replace the relay.


103

Diagnosis (Electronic Control Units)

In the following illustration, the ECU is programmed to light the bulb when switch “A” and switch“B” are ON and switch “C” is OFF. To diagnose a symptom of non-operation, separate the inputand output sides of the circuits. Begin by checking the output at the ECU wire connector.Remember, ECU-controlled outputs have the same requirements for source, load, and ground asany relay-controlled circuit. If an output signal is present, disconnect the ECU wire connectorand check the operation of the load with a jumper wire. Depending on how the load is wired,apply either voltage or ground for the load to operate.

If the load operates when source or ground is applied, go to the input side of the ECU circuit.With the wire connector removed from the ECU, check the inputs at the ECU wire connector tobe sure they are good. As in the example shown, some ECU output loads require more than oneinput to operate. If the inputs are good and there is no output to the load, the ECU is defective.

Diagnosis (Thermistor circuits)Diagnosis (Thermistor circuits)Diagnosis (Thermistor circuits)Diagnosis (Thermistor circuits)Diagnosis (Thermistor circuits)

To diagnose circuits containing thermistors, check the resistance of the thermistor and comparethat to specifications. Then check circuit continuity between the ECM and the load (thermistor).


104

Motors

Symptoms

• Motors are controlled by a switch, a relay or an ECU (Electronic Control Unit). If anelectrical failure occurs, it could be caused by an open circuit, preventing the motor fromoperating. A short circuit inside the motor or within the circuit will cause the fuse or fusiblelink to fail.

• Motors can also fail mechanically. A mechanical failure will also cause the motor to beinoperative. If the motor armature binds (stops rotating), electrical resistance decreasesand amperage increases which causes the fuse to fail.

Diagnosis

• If a motor circuit does not operate, check the fuse or fusible link for the motor circuit. Formotor circuits that are relay controlled, use the same procedures to isolate the malfunctionas explained previously for other relay-controlled loads.

• Motors that must rotate in both directions are switch-controlled. For example, if a windowmotor is “stuck” in the down position there could be an open circuit in the “up” contacts ofthe switch. To quickly check a window motor circuit, switch the ignition ON and watch thevehicle interior lights. If the lights dim slightly when you press the window switch to the“down” position, there is a complete circuit through the motor “down” circuit. If the lights donot dim when pressing the switch to the “up” position, the switch could be bad. If the lightsdim when the switch is pressed to the “up” position, the motor could be mechanically stuck.

• If the fuse or fusible link is bad, use the isolation procedures for fused circuits to determinewhether the malfunction is electrical. If you suspect a mechanical failure, remove the motorfrom its operating position and bench test it by applying power and ground. Be sure to usetest wires with an in-line fuse. If the motor operates on the bench, check the linkage ormechanical components that the motor drives to be sure they are not binding. Check wirerouting during the inspection. Wires can sometimes get tangled in the linkage and groundthe motor circuit.


105

Meter and Gauge Diagnosis

Symptom: The speedometer reads inaccurately (too fast or too slow)

• Speed sensor malfunction. Check wiring harness continuity and check speed sensor signalaccording to service manual procedures and specifications. Check condition of speedsensor signal using CONSULT data monitor function.

• Vehicle may have oversize tires.

- Oversize tires reduce axle speed which reduces speedometer reading.

- If oversized tires are installed on the vehicle, no corrections should be made other than torecommend correct tire application.

• A problem with a speed sensor may also appear at the engine ECM as well as the A/T andASCD control units.

- The revolution sensor is the primary input. The speed sensor will tell the A/T controlunit when to shift if the revolution sensor circuit fails. If the speed sensor orrevolution sensor circuit fails, the transmission O.D. light should blink for 7 secondsafter every vehicle start indicating a code is stored in the A/T control unit. Don’tforget to verify proper cruise cable adjustments.

- A/T control unit: Speed sensor input is used as a backup for the revolution sensor input.Transmission may not indicate a symptom caused by a bad speed sensor.

- ASCD control unit: Speed may not set correctly if the control unit gets an inaccurate orerratic speed input. Check wiring harness continuity and speed sensor signal accordingto service manual specifications.

Symptom: Indicators do not operate

• Check battery voltage input to the combination meter/microcomputer.

- If voltage is not present, trace and diagnose the circuit back to the power source.

- If the fuse is blown, look for a short between the fuse and the speedometer.

Symptom: Fuel gauge has inaccurate indication

• Check fuel tank gauge unit adjustment according to service manual specifications.

- Check wiring harness continuity between the gauge unit and speedometer.

- If resistance is out of specification the gauge will register lower than normal fuel level.

• Check Nissan’s ASIST® system for additional possibilities.

• Inspect hose and pipe connections in tank for mechanical interference.


106

NoteNoteNoteNoteNote:Quest only• If resistance is higher than the specification, the gauge reading will be higher than

the actual fuel level; if resistance is lower than the specification, the gaugereading will be lower than the actual fuel level.

All other Nissan models:• If resistance is higher than the specification, the fuel gauge reading will be lower

than the actual fuel level; if resistance is lower than the specification, the gaugereading wil be higher than the actual fuel level.


107

Meter and Gauge Checks

Thermal Transmitter Check

To verify the thermal transmitter is operating properly, check the resistance between the terminalsof the thermal transmitter and body ground.

The thermal transmitter is a variable resistor that affects the temperature gauge by controllingcurrent (amperage) in the circuit.

60°C (140°F) Approx. 70-90 ý

100°C (212°F) Approx. 21-24 ý

WWWWWater Tater Tater Tater Tater Temperatureemperatureemperatureemperatureemperature ResistanceResistanceResistanceResistanceResistance

Fuel Tank Gauge Unit Check

To verify the unit operates properly, check the resistance between terminals 3 and 2 (see thefollowing diagram). (Note: To remove the fuel tank gauge unit refer to the FE section in theservice manual.)

The fuel tank gauge unit is a variable resistor that affects the fuel gauge reading by controllingcurrent (amperage) in the circuit.

NoteNoteNoteNoteNote: The illustration that follows is an example of a test and specification chart fora fuel tank gauge unit. Tank gauge units for each vehicle are not the same. Theresistance varies with each one, so be certain you refer to the service manualwhen performing this procedure.

Float Position, mm (in.)Float Position, mm (in.)Float Position, mm (in.)Float Position, mm (in.)Float Position, mm (in.) ResistanceResistanceResistanceResistanceResistanceVVVVValue (ý)alue (ý)alue (ý)alue (ý)alue (ý)

Approx. 4-6

31-34

80-83

*1

*2

*3

3

OhmmeterOhmmeterOhmmeterOhmmeterOhmmeterconnectionconnectionconnectionconnectionconnection

2

1999 Pathfinder

Full

1/2

Empty

95 (3.74)

184 (7.24)

265 (10.43)

+ –+ –+ –+ –+ –

*1 and *3: When float rod is in contact with stopper


108

Nissan Original Equipment Battery RatingsNissan Original Equipment Battery RatingsNissan Original Equipment Battery RatingsNissan Original Equipment Battery RatingsNissan Original Equipment Battery RatingsNote: For original equipment batteries, the label showing the rating is located on the top of the batteryNote: For original equipment batteries, the label showing the rating is located on the top of the batteryNote: For original equipment batteries, the label showing the rating is located on the top of the batteryNote: For original equipment batteries, the label showing the rating is located on the top of the batteryNote: For original equipment batteries, the label showing the rating is located on the top of the battery

ModelModelModelModelModel YYYYYearearearearear ApplicationApplicationApplicationApplicationApplication RatingRatingRatingRatingRating

Xterra 2000 & later Standard 490 CCA2000 & later Optional 550 CCA

Quest 1997-98 All 550 CCA1999 & later All 525 CCA

Truck 1997 All 490 CCAFrontier 1998 & later All 490 CCA

1997 & later Standard 55D23RPathfinder 1997-99 Optional 75D31R

1999.5 Optional 80D26R200SX 1997-98 Standard 490 CCA

1997-98 Optional 550 CCASentra 1997 & later All 490 CCAAltima 1997 & later All 550 CCA240SX 1997-98 All 55D23R

2000 & later All 80D26LMaxima 1997-99 Standard 55D23L

1997-99 Optional 80D26L

*CCA = Cold Cranking Amps

Genuine Nissan Replacement Battery RatingsGenuine Nissan Replacement Battery RatingsGenuine Nissan Replacement Battery RatingsGenuine Nissan Replacement Battery RatingsGenuine Nissan Replacement Battery RatingsNote: For original equipment batteries, the label showing the group rating (i.e., 24, 25, 27, etc.) is located on the top of the batteryNote: For original equipment batteries, the label showing the group rating (i.e., 24, 25, 27, etc.) is located on the top of the batteryNote: For original equipment batteries, the label showing the group rating (i.e., 24, 25, 27, etc.) is located on the top of the batteryNote: For original equipment batteries, the label showing the group rating (i.e., 24, 25, 27, etc.) is located on the top of the batteryNote: For original equipment batteries, the label showing the group rating (i.e., 24, 25, 27, etc.) is located on the top of the battery

ModelModelModelModelModel YYYYYearearearearear ApplicationApplicationApplicationApplicationApplication Group #Group #Group #Group #Group # Nissan P/NNissan P/NNissan P/NNissan P/NNissan P/N CCA*CCA*CCA*CCA*CCA*

Altima 1993 & later All 24F 999M1-NB24F 575Axxess 1990 All 35 999M1-NB35C 525

1985 & later All 35 999M1-NB35C 525Maxima 1985 & later With cold package24F 999M1-NB24F 575

1984 All 25 999M1-NB25C 525Pulsar 1984-90 All 35 999M1-NB35C 525

1987-92 All 35 999M1-NB35C 525Stanza 1984-86 All except Wagon 25 999M1-NB25C 525

1986-88 Wagon 35 999M1-NB35C 5251987- & later All 35 999M1-NB35C 525

Sentra 1985-86 All except diesel 24F 999M1-NB24F 5751984 All except diesel 35 999M1-NB35C 525

Pathfinder 1987 & later All 25 999M1-NB25C 5251987 & later All with heated seats 24 999M1-NB24C 575

Frontier 1999 & later Four cylinder 25 999M1-NB25C 5251999 & later Six cylinder 24 999M1-NB24C 5751984-97 All except diesel 25 999M1-NB25C 525

Truck 1986 Diesel 24 (2) 999M1-NB24C 5751982-85 Diesel 27 999M1-NB27C 660

Quest 1993 & later All 24F 999M1-NB24F 575Van 1987-90 All 25 999M1-NB25C 525200SX 1995 & later All 25 999M1-NB35C 525

1982-88 All 24 999M1-NB24C 5751995-98 All 25 999M1-NB25C 525

240SX 1989-94 All exc. convertible 24 999M1-NB24C 5751992-94 Convertible 25 999M1-NB25C 5251990-96 All 24F 999M1-NB24F 575

300ZX 1992-96 Convertible 35 999M1-NB35C 5251984-89 All 25 999M1-NB25C 525

Xterra 2000 & later All (standard) 25 999M1-NB25C 5252000 & later All (optional) 24 999M1-NB24C 575


109

GLOSSARY OF TERMS

Alternating Current (AC)Alternating Current (AC)Alternating Current (AC)Alternating Current (AC)Alternating Current (AC) - Current that reverses its direction at regular intervals.

Amperes Amperes Amperes Amperes Amperes (amps) - Unit of measure for current flow in an electrical circuit.

AmmeterAmmeterAmmeterAmmeterAmmeter - An electrical test meter that measures the amount of current flow, in amperes, in acircuit.

Analog multimeterAnalog multimeterAnalog multimeterAnalog multimeterAnalog multimeter - A device that measures voltage, resistance and current. The numericalmeasurement is represented by a dial-type needle that points to the numerical value on one ofmany scale ranges.

Battery Battery Battery Battery Battery - A device consisting of two or more cells for converting chemical energy into electricalenergy.

Coil Coil Coil Coil Coil - Thin wire wound into a circular shape, usually around an iron core. Current passingthrough the coil creates a strong magnetic field to assist in electrical contacts and other circuitfunctions.

CircuitCircuitCircuitCircuitCircuit - An assembly consisting of a voltage source, a load, a control device (such as a switchand a ground path. A circuit carries electricity through a load to produce some type of work, suchas heat, light or motion.

Circuit breakerCircuit breakerCircuit breakerCircuit breakerCircuit breaker - A mechanism designed to break or open the circuit when certain conditionsexist; usually heat sensitive.

Circuit protectionCircuit protectionCircuit protectionCircuit protectionCircuit protection - A device which is used to protect wiring and electrical devices fromexcessive current flow, so that they are not damaged.

Combination Circuit - Combination Circuit - Combination Circuit - Combination Circuit - Combination Circuit - A circuit which combines series and parallel circuits.

ConductorConductorConductorConductorConductor - The device which connects electrical components together so current can flow in acircuit. Electrical conductors are more commonly referred to as wires. The most commonconductors are copper and aluminum, but gold is also a good conductor. The metal vehiclechassis is also a conductor.

ConnectorConnectorConnectorConnectorConnector - A mechanical device to connect single or multiple terminals. Usually surrounded byan insulating material to electrically separate the conducting material.

ContinuityContinuityContinuityContinuityContinuity - A complete path for current flow. In the service manual, continuity does NOTnecessarily mean “0” ohms resistance.

Conventional current flow theoryConventional current flow theoryConventional current flow theoryConventional current flow theoryConventional current flow theory - The theory that states that current flows from the positivepost of the battery through the external source side of the circuit, through the circuit loads andback to the battery via the ground circuit.

GLOSSARY OF TERMS

110

Crossed CircuitCrossed CircuitCrossed CircuitCrossed CircuitCrossed Circuit - A malfunction. Current flow from a switch operates a LOAD from a different,unrelated circuit.

Current FlowCurrent FlowCurrent FlowCurrent FlowCurrent Flow - The movement of electrons in a circuit. Also called amperage or electricity.

Digital Multimeter Digital Multimeter Digital Multimeter Digital Multimeter Digital Multimeter - A device that measures voltage, resistance and current. The numericalmeasurement is shown in numbers using a LCD or LED display. Also called a digital volt-ohmmeter.

Diode Diode Diode Diode Diode - An electrical device that acts like one-way check valve. It permits current flow in onedirection, but stops it from flowing in the other direction.

Direct Current (DC)Direct Current (DC)Direct Current (DC)Direct Current (DC)Direct Current (DC) - Current that flows in one direction only.

ECU ECU ECU ECU ECU - Electronic Control Unit. An electronic logic device to operate electronically-controlledcircuits.

ElectromagnetElectromagnetElectromagnetElectromagnetElectromagnet - A temporary magnet constructed by winding a number of turns of insulatedwire into a coil or around an iron core. It is energized by the flow of current through the coil. Usedin relays and solenoids.

FuseFuseFuseFuseFuse - A type of circuit protection device that has a thin metal segment that melts when its ratedcurrent-carrying capacity is exceeded. When this occurs, the circuit can not be completed untilthe faulty fuse is replaced.

Fuse block/junction block Fuse block/junction block Fuse block/junction block Fuse block/junction block Fuse block/junction block - A grouping of fuses. A connection point for circuit wires toseparate to other circuits.

Fusible linkFusible linkFusible linkFusible linkFusible link - A type of circuit fuse that uses a length of heat sensitive conducting wire toprotect a circuit.

Grounded Circuit Grounded Circuit Grounded Circuit Grounded Circuit Grounded Circuit - A circuit in which there is an unwanted contact between a conductor andground. On the SOURCE side of a circuit, this will cause the fuse to blow. On the ground side ofthe circuit, the LOAD may be ON all the time.

Group # (battery) Group # (battery) Group # (battery) Group # (battery) Group # (battery) - The storage battery size to mount into a specific vehicle.

InsulatorInsulatorInsulatorInsulatorInsulator - A material that will not allow current flow. Also, the material that separatesconductors, providing a barrier that shields them from interfering with each other. Insulators aremore commonly referred to as the wrapping, or sheaths around wires. The most commoninsulating materials are plastic and rubber because they have excellent insulating properties yetremain very flexible.

Light emitting diode (LED)Light emitting diode (LED)Light emitting diode (LED)Light emitting diode (LED)Light emitting diode (LED) - A type of diode that emit light when current flows from anode tocathode. They normally emit red light, but other colors are available, including INFRA-RED LEDs.They conduct current in one direction only, but can be damaged by reverse voltages.

GLOSSARY OF TERMS

111

Magnetic fieldMagnetic fieldMagnetic fieldMagnetic fieldMagnetic field - The property exhibited by certain substances and produced by electron (orelectric current) motion which results in the attraction of iron.

Motor Motor Motor Motor Motor - A device for converting electrical energy into mechanical energy.

Multimeter - Multimeter - Multimeter - Multimeter - Multimeter - A device that measures voltage, resistance and current (see analog and/or digitalmultimeter).

OhmsOhmsOhmsOhmsOhms - Unit of measure for resistance of electrical devices or circuits.

Ohm’s Law - Ohm’s Law - Ohm’s Law - Ohm’s Law - Ohm’s Law - A basic statement of the relationship between volts, amps and ohms.

Ohmmeter Ohmmeter Ohmmeter Ohmmeter Ohmmeter - A device for measuring ohms resistance of a circuit or electrical device.

Open CircuitOpen CircuitOpen CircuitOpen CircuitOpen Circuit - An incomplete circuit in which current cannot flow from SOURCE to LOAD toGROUND because of a disconnection, broken wire, blown fuse or other interruption.

Parallel circuitParallel circuitParallel circuitParallel circuitParallel circuit - A circuit in which there is a separate path for current flow for each LOAD. If oneof the LOADs has an open circuit, the other loads will continue to operate.

Potentiometer Potentiometer Potentiometer Potentiometer Potentiometer - A variable resistor that is mechanically operated.

Parasitic load (draw)Parasitic load (draw)Parasitic load (draw)Parasitic load (draw)Parasitic load (draw) - Electrical current from the battery that exists when the vehicle is notoperating.

PolarityPolarityPolarityPolarityPolarity - A term relating to the direction of current flow in a circuit. For instance, a circuit is saidto have positive polarity when the current flows from positive to negative.

Primary ignition (primary circuit)Primary ignition (primary circuit)Primary ignition (primary circuit)Primary ignition (primary circuit)Primary ignition (primary circuit) - Equivalent to SOURCE voltage; the circuit used to signal orswitch the ignition system.

Rectifier (rectify)Rectifier (rectify)Rectifier (rectify)Rectifier (rectify)Rectifier (rectify) - An electrical device that changes alternating current to direct current.

RelayRelayRelayRelayRelay - An electrically-operated switch that uses low current flow in the coil control circuit toactivate higher current flow in the contact point circuit.

Reserve capacityReserve capacityReserve capacityReserve capacityReserve capacity - The ability of a battery to sustain current output when connected to a circuitor a specified test load. Storage batteries are usually rated in Cold Cranking Amperes (CCA).

ResistanceResistanceResistanceResistanceResistance - The opposition or reluctance to current flow in a circuit. Resistance is expressed inohms, represented by the symbol Ω (omega).

Secondary ignition (secondary circuit)Secondary ignition (secondary circuit)Secondary ignition (secondary circuit)Secondary ignition (secondary circuit)Secondary ignition (secondary circuit) - The circuit that creates a high voltage spark; operateswith and controlled by the primary circuit.

Semi-conductorSemi-conductorSemi-conductorSemi-conductorSemi-conductor - A device that is neither an insulator nor a conductor. With certain materialsadded to their makeup, semi-conducting devices can be made into conductors. Semi-conductors are more commonly known as transistors, diodes and electronic control devices.

GLOSSARY OF TERMS

112

Series circuitSeries circuitSeries circuitSeries circuitSeries circuit - A circuit in which there is only a single path for current flow. If one of thecomponents or LOADS in the circuit becomes open, the circuit no longer operates.

Series-parallel circuit Series-parallel circuit Series-parallel circuit Series-parallel circuit Series-parallel circuit - The electrical circuit formed when series-connected circuit elements arecombined with parallel-connected circuit elements.

Shorted CircuitShorted CircuitShorted CircuitShorted CircuitShorted Circuit - A circuit in which current flow takes a shorter path (less resistance) betweenSOURCE and GROUND, bypassing part or all of the circuit LOAD. Short circuits increasecurrent flow and can cause blown fuses.

SolenoidSolenoidSolenoidSolenoidSolenoid - A device that allows electricity to pass through a coil of wire to create magnetism. Amechanical lever moves as a result of the electromagnetism.

SourceSourceSourceSourceSource - A supply of voltage to operate a circuit.

Specific gravitySpecific gravitySpecific gravitySpecific gravitySpecific gravity - The ratio of the weight of a substance to the weight of an equal volume ofchemically pure water at 39.2°F; used to measure the state of charge of a lead-acid storagebattery.

Static electricityStatic electricityStatic electricityStatic electricityStatic electricity - Accumulated electrical charges, usually considered to be those produced byfriction.

Storage BatteryStorage BatteryStorage BatteryStorage BatteryStorage Battery - A lead-acid electrochemical device that changes chemical energy into electricenergy. The action is reversible; electrical energy applied to the battery stores chemical energy.

SulfationSulfationSulfationSulfationSulfation - A term used to describe a chemical condition that occurs within a battery when theelectrolyte has degraded to a condition that does not produce normal voltage. When a battery isheavily sulfated, the electrolyte and plate material combine into a hardened substance (thesulfate) which settles to the bottom of a cell, causing the cell to not accept a charge or delivercurrent. When this occurs, the battery is not serviceable because this condition is irreversible.

TTTTTerminal erminal erminal erminal erminal - The metal connector attached to the end of a length of stranded wire which is used toconnect to another component or wire.

ThermistorThermistorThermistorThermistorThermistor - An electronic component that changes its resistance as its temperature changes.

TTTTTransistorransistorransistorransistorransistor - A semiconductor switching device. Can be used as a switch or a relay.

VVVVVariable Resistorariable Resistorariable Resistorariable Resistorariable Resistor - A component whose resistance value can be changed to change tooperation of a LOAD in a circuit.

VVVVVoltoltoltoltolt - A unit of measure of electrical pressure (voltage).

VVVVVoltageoltageoltageoltageoltage (electrical potential) - The electrical pressure required to push a current of electricitythrough a circuit. Voltage is chemically produced in a lead-acid battery or from anelectromagnetic field, such as in an alternator.

GLOSSARY OF TERMS

113

VVVVVoltage drop(s)oltage drop(s)oltage drop(s)oltage drop(s)oltage drop(s) - The amount of voltage consumed by a LOAD during circuit operation. The totalof all voltage drops in a circuit is equal to the available voltage. A concept which describes whatoccurs in a circuit when current passes through a load. A load in this case is loosely defined asanything that causes resistance. This can include corrosion or looseness in wiring andconnections, fixed or variable resistance, or devices such as bulbs or motors.

VVVVVoltmeteroltmeteroltmeteroltmeteroltmeter - An electrical test meter that measures the amount of voltage or electrical pressure ina circuit.

Wiring/ wire gauge Wiring/ wire gauge Wiring/ wire gauge Wiring/ wire gauge Wiring/ wire gauge - Diameter of a wire. Smaller gauge wire (larger number) can carry lesscurrent.

Zener diode Zener diode Zener diode Zener diode Zener diode - A semiconductor. This type of diode conducts electricity in the reverse directionfrom normal diodes. To pass electricity through a zener diode, it must be around eight to tentimes the value of the normal diode, typically 4.7volts. When four diodes are connected in acertain way (i.e., "bridged") they will convert AC to DC, as in an alternator.

GLOSSARY OF TERMS

114

NOTES

NOTES

MODULES

i

Date of ClassDate of ClassDate of ClassDate of ClassDate of Class

ELECTRICAL COMPONENT DIAGNOSIS AND REPAIRSIGN-OFF SHEET

WORKSHEET TITLE INSTRUCTOR

Module 1 Locate Service Manual Information

Module 2 Interpret Service Manual Information

Module 3 Measuring Available Voltage

Module 4 Measuring Voltage Drop

Module 5 Measuring Resistance

Module 6 Measuring Current

Module 7 Combination Switch Operation

Module 8 Diagnosing One Transfer (1T) Relay Malfunctions

Module 9 Diagnosing One Make (1M) Relay Malfunctions

Module 10 Diagnosing Two Make (2M) Relay Malfunctions

Module 11Diagnosing One Make-One Break (1M-1B) RelayMalfunctions







Module 18 How to Use a Digital Multimeter

Module 19 Fuel Guage Unit Testing

Module 20 Service Manual Electrical Symbols

Module 21 Testing Batteries, Starters & Charging Systems

ii

ELE

CTR

ICA

L CO

MP

ON

EN

T DIA

GN

OS

IS A

ND

RE

PA

IRC

OU

RS

E M

AP

MeasuringAvailable Voltage

Module 3Module 3Module 3Module 3Module 3

MeasuringVoltage Drop


MeasuringResistanceModule 5Module 5Module 5Module 5Module 5

MeasuringCurrent


Service ManualElectrical Symbols


Locate ServiceManual

InformationModule 1Module 1Module 1Module 1Module 1

Interpret ServiceManual

InformationModule 2Module 2Module 2Module 2Module 2

IntroductionTerminology

Service ManualMeter Familiarization

How to Use aDigital Multimeter


iii

Fuel Gauge TankUnit TestingModule 19Module 19Module 19Module 19Module 19

Testing Batteries,Starters & Charging

SystemsModule 21Module 21Module 21Module 21Module 21

CombinationSwitch Operation


DiagnosingOne Make (1M)

Relay MalfunctionsModule 9Module 9Module 9Module 9Module 9

DiagnosingOne Transfer (1T)


Diagnosing One Make-One Break (1M-1B)Relay Malfunctions


DiagnosingTwo Make (2M)


Circuit DiagnosisExercise: #2Module 13Module 13Module 13Module 13Module 13






iv

NOTES

1Module 1

Module 1

Objective:Objective:Objective:Objective:Objective: Given an Electronic Service Manual(ESM), locate wiring diagramdescriptions and interpret theinformation.

Relevance:Relevance:Relevance:Relevance:Relevance: An important part of vehicle repair isthe ability to locate diagnostic repairinformation.

Both the General Information General Information General Information General Information General Information (((((GIGIGIGIGI)))))and Electrical (EL)Electrical (EL)Electrical (EL)Electrical (EL)Electrical (EL) sections of theservice manual contain usefulinformation relating to circuit operationand testing.

Resources:Resources:Resources:Resources:Resources: ASIST/ESM

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: You will locate and identify electricalcomponents, symbols and informationin the ESM.

You will identify navigation controls inthe ESM.

LOCALOCALOCALOCALOCATE SERVICE MANUAL INFORMATE SERVICE MANUAL INFORMATE SERVICE MANUAL INFORMATE SERVICE MANUAL INFORMATE SERVICE MANUAL INFORMATIONTIONTIONTIONTION

2 Module 1

ECTC0016C

Use the ESM to answer the following questions:

1. On what page in the GI section is thecombination switch located? (See illustration onleft).

Page GIGIGIGIGI-_________________

2. What page describes the connector symboldescriptions?

Page GIGIGIGIGI- _________________

3. In the illustration on the left, draw a circle aroundeach symbol that identifies a male connector.

4. Locate the pages that describe standardizedrelays in the service manual.

What color is a 2M relay case?

__________________________

5. What pages in the ELELELELEL section describe PowerSupply routing?

Pages ELELELELEL-______ to ELELELELEL-________

6. Find the section that covers the location ofElectrical Units.

Other than relays, which other components arelocated in boxes under the hood?

____________________________________

3Module 1

Module 1

7. Locate the CHARGING SCHARGING SCHARGING SCHARGING SCHARGING SYYYYYSTEMSTEMSTEMSTEMSTEM wiringdiagram in the service manual. What is theconnector number for the Charge WarningLamp?

M__________________________________

The chart on the left shows wiring harness codeprefixes (“M” for main harness).

8. Find main harness connector locatorinformation.

What is the grid coordinate for the location ofthe charge warning lamp connector?

__________________________________

9. Using the illustration of the A/T control unitconnector below as a reference, which side ofthe connector is in view?

____________________________________

IIIII Instrument

SSSSS Sunroof

DDDDD Door

BBBBB Body

Z Z Z Z Z Air Bag

MMMMM Main

EEEEE Engine

FFFFF Eng. Control (EFI)

AAAAA Alternator

TTTTT Tail

RRRRR Room (Interior Lamp)

Harness SymbolsHarness SymbolsHarness SymbolsHarness SymbolsHarness Symbols

4 Module 1

ECTC0016C

10. Some service manuals also show jointconnector (J/C) locations. A joint connectorshows that two or more wires are electricallyjoined together in a connector or a junction box.

In the illustration below, which terminals arejoined together in connector M1?

____________________________________

5Module 1

Module 1

11. Using the GIGIGIGIGI section as a reference, match theletter of each service procedure with thecorresponding symbol in the spaces provided.

a. Disconnectb. Switch ignition to ONc. Harness side of connectord. Measure with an ohmmetere. Do not start

12. Using the ELELELELEL section as a reference, what typeof relay has a gray case?

______________ Page ELELELELEL-____

13. Where is the ECM located?

____________________________________

14. Locate the Power Supply Routing schematic inthe ELELELELEL section of the service manual.

What amperage fuse protects the horn circuit?

_____ Amp Page ELELELELEL-____

What is the fuse number? _______________

15. What do the two symbols at left represent?

a. _________________________________

b. _________________________________

a b

6 Module 1

ECTC0016C

16. Using the engine compartment Harness Layoutpage as a reference, which componentconnects to connector E15?

___________________________________

17. Find the engine control Harness Layout page.

What is the connector number for the ThrottlePosition Switch?

_______________ Page ELELELELEL-_____

18. Identify the following navigation controls in theESM by placing the cursor over the icon.

___ Bookmark options___ Last views___ Search Commands___ Open navigation menu___ Print document or selected page(s)___ View first, previous, next or last page

BBBBB EEEEEDDDDDAAAAACCCCC

FFFFF

7Module 1

Module 1

When using the ESM or ASIST, you have the abilityto do keyword searches. Hold down the Ctrl Ctrl Ctrl Ctrl Ctrl key andselect the letter “F” to begin the search.

19. Located in the lower left corner of the keyboardis the Ctrl Ctrl Ctrl Ctrl Ctrl key. Hold down the Ctrl key and thenpress the letter FFFFF.

20. Place the cursor in the box and type the word“Power”. Then select findfindfindfindfind. You should havelocated the next place in this section with theword “Power”.

You have just completed this worksheet. You shouldnow be able to locate necessary information to readwiring diagrams. If you have any doubt about yourskills in completing this worksheet, please return tostep 1 and review your work. Once you are confidentof your skills, have your instructor verify your work.

Instructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s Initials ______________________

••••• Return the workstation to the conditionReturn the workstation to the conditionReturn the workstation to the conditionReturn the workstation to the conditionReturn the workstation to the conditionthat you found it.that you found it.that you found it.that you found it.that you found it.

8

NOTES

Module

1Module 2

Module 2

Objective:Objective:Objective:Objective:Objective: Given an electronic service manual,interpret wiring diagram symbols andanswer related questions.

Relevance:Relevance:Relevance:Relevance:Relevance: Your ability to diagnose electricalmalfunctions depends on how well youcan read and interpret vehicle wiringdiagrams.

Wiring diagrams illustrate how parts ofan electrical circuit fit together. Wiringdiagrams use electrical symbols todescribe switches, connectors,motors, relays and fuses. There arealso symbols for wire colors and whereand how these wires connect to eachother.

Resources:Resources:Resources:Resources:Resources: ESM

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: You will locate and identify electricalsymbols and their descriptions in theGIGIGIGIGI section of an ESM.

INTERPRETING SERVICE MANUAL INFORMAINTERPRETING SERVICE MANUAL INFORMAINTERPRETING SERVICE MANUAL INFORMAINTERPRETING SERVICE MANUAL INFORMAINTERPRETING SERVICE MANUAL INFORMATIONTIONTIONTIONTION

2 Module 2

ECTC0016C

Use the GIGIGIGIGI section in the ESM to answer questions1–16.

1. This illustration shows two halves of aconnector.

Circle the male side of the connector.

2. The numbers in this connector representterminal numbers.

What is the terminal number for the ‘W’ wire?

___________________________________

What is the terminal number for the ‘B/W’ wire?

___________________________________

3. Locate the service manual page that describesthe code for wire colors.

Record the correct wire color next to the colorcode in the space provided in the chart.

4. What do B1 and D0 represent in thisillustration? (Check one)

Connector location

Super multiple junction terminal location

Multiple switch terminal location

B= BR=

L= GY=

P= PU=

LG= SB=

G/B= OR/B=

G/R= Y/L=

3Module 2

Module 2

5. What do E5 and M4 indicate in the illustration?(Check one)

Component location

Connector number

Terminal number

6. What is the normal position of each of theseswitches?

Switch A: __________________________

Switch B: __________________________

7. Match the symbol on the left with the letter of itsdescription below:

A. Do not start engine, or check withengine stopped.

B. Circuit resistance should be measuredwith an ohmmeter.

C. Check after disconnecting theconnector to be measured.

D. Turn ignition switch from “ON” to“OFF”.

E. Voltage should be measured with avoltmeter.

F. View from the harness side.

G. Start engine, or check with enginerunning.

H. Check after connecting the connectorto be measured.

VVVVV

4 Module 2

ECTC0016C

8. Examine the sample wiring diagram shown in theGIGIGIGIGI section. There are two types of wire splices:

What do these symbols mean?

a. _________________________________

b. _________________________________

9. What type of meter is being used for thediagnosis shown at left?

Ammeter / Ohmmeter / VAmmeter / Ohmmeter / VAmmeter / Ohmmeter / VAmmeter / Ohmmeter / VAmmeter / Ohmmeter / Voltmeteroltmeteroltmeteroltmeteroltmeter (Circle one)

10. What connector terminals must be tested?

__________________________________

11. On which side of the harness should youperform the inspection?

TTTTTerminal / Harnesserminal / Harnesserminal / Harnesserminal / Harnesserminal / Harness (Circle one)

12. For the inspection shown at left, the harnessconnector should be:

Connected / DisconnectedConnected / DisconnectedConnected / DisconnectedConnected / DisconnectedConnected / Disconnected (Circle one)

13. The engine should be:

ON / OFF ON / OFF ON / OFF ON / OFF ON / OFF (Circle one)

14. What electrical test must be done?(Check one)

Measure amperage

Measure resistance

Measure voltage

5Module 2

Module 2

15. Which connector terminal must be tested?

___________________________________

16. Which side of the connector is the meter beingprobed?

TTTTTerminal side / Harness side erminal side / Harness side erminal side / Harness side erminal side / Harness side erminal side / Harness side (Circle one)

Refer to the charging system wiring diagram in theESM for answers to questions 17–21.

17. What types of circuit protection devices areused in the charging system?

___________________________________

___________________________________

18. Both the fusible link and fuse shown at left haveclear and dark circles. What do these circlesmean?

___________________________________

___________________________________

19. How many pin openings are there in the chargewarning lamp connector?

___________________________________

20. What type of splice connects the battery to thecharging circuit?

___________________________________

21. Where is the alternator ground attached to thevehicle? (Check one)

To a body ground under the dashboard

To a body ground behind the right kick panel

To a body ground in the engine compartmentor to a chassis ground under the hood

Fusible link Fuse

6 Module 2

ECTC0016C

Refer to the illustration at left to answer questions22–27.

22. To perform the test shown, should bothconnectors be connected?

YES / NOYES / NOYES / NOYES / NOYES / NO (Circle one)

23. These connectors are both:

Male / FemaleMale / FemaleMale / FemaleMale / FemaleMale / Female (Circle one)

24. What type of measurement is called for in thisstep? (Check one)

Circuit voltage measurement

Circuit resistance measurement

Circuit amperage measurement

25. In what position must the ignition switch be set?

ON / OFF ON / OFF ON / OFF ON / OFF ON / OFF (Circle one)

26. What two terminals must be tested?

_____ and _____

27. Which side of the C/UNIT CONNECTOR mustbe tested?

TTTTTerminal side / Harness side erminal side / Harness side erminal side / Harness side erminal side / Harness side erminal side / Harness side (Circle one)

7Module 2

Module 2

Refer to the illustration on the left to answerquestions 28–33.

28. What type of measurement is being performed? (Check one)

Check circuit voltage

Check circuit resistance

Check circuit amperage

29. What pedal is being applied?

Brake / Accelerator Brake / Accelerator Brake / Accelerator Brake / Accelerator Brake / Accelerator (Circle one)

30. What is the color of the wire connected toterminal 1?

___________________________________

31. Is this inspection done with the connectorseparated?

YES / NO YES / NO YES / NO YES / NO YES / NO (Circle one)

32. What does ‘M107’ refer to?

___________________________________

33. On which side of the connector should themeter be connected?

TTTTTerminal side/Harness side erminal side/Harness side erminal side/Harness side erminal side/Harness side erminal side/Harness side (Circle one)

You have just completed this worksheet. You shouldnow be able to interpret wiring diagram symbols andanswer related questions. If you have any doubtabout your skills in completing this worksheet pleasereturn to step 1 and review your work. Once you areconfident of your skills, have your instructor verify yourwork.

Instructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s Initials _____________________

Return the workstation to the condition in whichReturn the workstation to the condition in whichReturn the workstation to the condition in whichReturn the workstation to the condition in whichReturn the workstation to the condition in whichit was found.it was found.it was found.it was found.it was found.

8

NOTES

Module 2

1Module 3

Module 3Objective:Objective:Objective:Objective:Objective: Given a multimeter, a circuit simulator

and a windshield wiper motor circuit,measure available voltage at differentpoints in a circuit and makecomparisons for the purpose ofdiagnosing faults.

Relevance:Relevance:Relevance:Relevance:Relevance: Voltage is electrical pressure. Thiselectrical pressure is necessary topush current through a circuit. Avoltmeter is used to measure voltageand can be very beneficial when usedas a diagnostic tool for testingelectrical malfunctions.

Resources:Resources:Resources:Resources:Resources: • Digital multimeter• ESM• Circuit simulator

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: You will build a circuit and testavailable voltage.

You will locate and identify thewindshield wiper motor circuit on atest vehicle and measure the availablevoltage.

MEASURING AMEASURING AMEASURING AMEASURING AMEASURING AVVVVVAILABLE VOLAILABLE VOLAILABLE VOLAILABLE VOLAILABLE VOLTTTTTAGEAGEAGEAGEAGE

2 Module 3

ECTC0016C

1. Using the drawing in figure 1, build the circuit onthe simulator overlay. Use the parts provided tobuild this circuit.

Switch the circuit ON to verify the load works,then switch it OFF.

2. Rotate the selector knob on the meter to selectDC Volts (V ).

3. Connect the red test lead to the V input jack andthe black test lead to the COM (common) inputjack.

Overlay #1Switch on negative side of circuit

Red

Black

Figure 1Figure 1Figure 1Figure 1Figure 1

3Module 3

Module 3

4. Connect the red test lead to the battery positive(+) terminal on the simulator and the black testlead to the battery negative (–) terminal on thesimulator (Figure 2).

5. Switch the circuit ON.

6. Measure available voltage at the battery, thenrecord the reading at left.

Note:Note:Note:Note:Note: This measurement indicates the voltageavailable during circuit operation. Testing foradequate available voltage should be the firstcircuit measurement you make.

This also confirms that the meter and testleads are in good working order. Batteryvoltage less than 12 volts indicates a potentialproblem.


RECORDANSWER

EEEEE

AAAAA BBBBB

CCCCCDDDDD

4 Module 3

ECTC0016C

7. Leave the black lead connected to the batterynegative and move the red lead to the positiveterminal of the load (Figure 2, position AAAAA).

With the switch still ON (closed), measure thevoltage and record the reading in the space atleft.

Note:Note:Note:Note:Note: This measurement indicates the voltageavailable at the load. This reading should beslightly less than measured in step 6. Lowvoltage readings indicate high resistancebetween the power supply and the load. Lowvoltage may result in false codes being storedin ECM-controlled circuits.

A voltage reading close to the source voltageconfirms continuity between the battery andthe load, which means the wiring is good.

8. Leave the black lead connected to the batteryground and move the red lead to the groundside of the load (Figure 2, position BBBBB).

9. Turn the circuit switch OFF (open switch) andmeasure the voltage on the ground side of theload. Record your answer at left.

Based on this meter connection, is there voltageimmediately after the load?

____________________________________

Is the load operating at this time? ________

Why do you think this is the case?

____________________________________

____________________________________

____________________________________

RECORDANSWER

RECORDANSWER

5Module 3

Module 3

10. Now close the switch (circuit ON) and recordthe voltmeter reading in the space at left.

Instructor’s Initials Instructor’s Initials Instructor’s Initials Instructor’s Initials Instructor’s Initials _______________________

RECORDANSWER

RECORDANSWER

11. Have your instructor assign a test vehicle for thefollowing voltage measurement exercises.

12. Set up the meter to measure DC volts.

Connect both meter leads to the battery andrecord the battery voltage at left.

13. With the ignition switch OFF, measure availablevoltage to all fuses.

Note:Note:Note:Note:Note: On newer vehicles, all fuses are numbered inthe fuse box. If you cannot read the numbers,use a flashlight or a drop light.

Connect the black lead to ground and the redlead to each fuse in the fuse box.

Is battery voltage available to all the fuses?


Why?

___________________________________

___________________________________

Note:Note:Note:Note:Note: When testing circuit operation, refer to theappropriate wiring diagram to determine whichswitches (if any) must be ON beforemeasuring available voltage.

6 Module 3

ECTC0016C

14. To test the windshield wiper motor circuit, switchthe ignition ON (engine OFF) and measureavailable voltage to the windshield wiper motor.

• Find the wiper motor wiring diagram inthe ELELELELEL section of the service manual.

• Using this diagram, trace the wiper motorvoltage feed wire from the wiper fuse to thewiper motor.

15. What color is this wire on the test vehicle?

___________________________________

16. Disconnect the connector, locate the wireterminal feeding this circuit, then measure andrecord the voltage in the space provided at left.

Note:Note:Note:Note:Note: This reading should be about the same as theavailable battery voltage. By confirming thatthe wiper motor has voltage available, youknow the fuse, wiring, connections and batteryare in good working order ... up to the load. Inother words, the source side of the circuit isokay.

If a complaint of “wipers don’t work” werepresented, the load and the ground path arethe only things left to check.

You have just completed this worksheet. You shouldnow be able to measure available voltage at differentpoints in a circuit and make comparisons for thepurpose of diagnosing faults. If you have any doubtabout your skills in completing this worksheet pleasereturn to step 1 and review your work. Once you areconfident of your skills, have your instructor verify yourwork.


Return the workstation to the condition inReturn the workstation to the condition inReturn the workstation to the condition inReturn the workstation to the condition inReturn the workstation to the condition inwhich it was found.which it was found.which it was found.which it was found.which it was found.

RECORDANSWER

1Module 4

Module 4

Objective:Objective:Objective:Objective:Objective: Given a voltmeter, an ElectricalLighting Simulator and an assignedvehicle, measure voltage drop asspecified and evaluate the resultsagainst established specifications.

Relevance:Relevance:Relevance:Relevance:Relevance: During circuit operation, it is normal forelectrical loads to use up the bulk ofthe available voltage to makethem operate. Circuit connections,wiring and grounds may also cause anominal amount of voltage dropthrough each connection.

By using a voltmeter to measurevoltage drop at different points in acircuit, you can quickly isolate the partof the circuit that causes faulty circuitoperation (e.g. loose, dirty or damagedconnections).

Resources:Resources:Resources:Resources:Resources: • Digital Multimeter• Test vehicle equipped with rear window defogger• Electrical Lighting Simulator

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: You will measure the voltage drop in alighting circuit.

On a test vehicle, you will measurevoltage drop in a rear windowdefogger circuit.

MEASURING VOLMEASURING VOLMEASURING VOLMEASURING VOLMEASURING VOLTTTTTAGE DROPAGE DROPAGE DROPAGE DROPAGE DROP

2 Module 4

ECTC0016C

Use the Electrical Lighting Simulator to perform steps1–8.

1. Switch the headlights ON.

2. Measure available voltage at the source (batteryvoltage), by connecting the multimeter to thebattery. Record the reading here.

____________ Volts

Test voltage drops as follows:

3. Connect the red lead to the battery positivecable and the black lead to the source side ofthe headlamp (closest to battery).

4. Switch the circuit ON and measure the voltagedrop between these points. The voltage readingdisplayed on the meter is the voltage dropbetween the battery and the load. Record thereading here.

____________ Volts

Note:Note:Note:Note:Note: Voltage drop must be measured with thecircuit operating. When measuring voltagedrop across a portion of the wiring, thevoltage drop reading should be very small.

Headlamp bulb

–––––––––– +

Vehicle frame (body ground)

Battery

–––––––––– +


Battery

3Module 4

Module 4

5. With the circuit still ON, move the black lead tothe ground side of the load. Move the red leadto source side of the headlamp. Record thereading here.

____________ Volts

Note:Note:Note:Note:Note: This reading is the voltage drop across theload. This reading should be very close tosource voltage. If it is not close to sourcevoltage, there is high resistance at some otherpoint in the circuit.

–––––––––– +


Battery

–––––––––– +


Battery

6. With the circuit still ON, measure voltage dropacross the ground circuit as follows:

• Move the red lead to the ground side of thesame load and the black lead to the batterynegative terminal.

• Record the reading here.

____________ Volts

4 Module 4

ECTC0016C

7. Add the readings obtained in steps 3–6 andrecord the total here.

_____________ Volts

Does this value equal the reading obtained instep 2?


Should they be the same?


Note:Note:Note:Note:Note: The sum of the voltage drops in a circuitshould equal the available source voltage.

While a circuit is operating, the ground sidevoltage drop should be .1 volt or less.

A voltage drop greater than .1 volt mayindicate lose, dirty or corroded connections ordamage within the wiring harness between thecircuit load and the battery negative cableconnection.

Instructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s Initials _______________________

8. Have your instructor assign you a test vehicleequipped with a rear window defogger systemto practice measuring voltage drop.

9. Switch the ignition and rear window defoggerON to activate the rear window defoggercircuit.

RECORDANSWER

Wire Connections

Ground connections

Switch contacts

Starter Solenoids

VVVVVoltage Drop Chartoltage Drop Chartoltage Drop Chartoltage Drop Chartoltage Drop Chart

Maximum Allowable Voltage Drop*

*These guidelines are not applicable to*These guidelines are not applicable to*These guidelines are not applicable to*These guidelines are not applicable to*These guidelines are not applicable toelectronically-controlled circuitselectronically-controlled circuitselectronically-controlled circuitselectronically-controlled circuitselectronically-controlled circuits

0.1 Volt or lessfor each connection

0.1 Volts

0.3 Volts

0.5 Volts

5Module 4

Module 4

10. Measure available voltage at the source side ofthe load and record it here (see illustrationat left).

_______________ Volts

11. Is this reading acceptable?

Rearwindowdefogger

–––––––––– +


Battery


12. Measure voltage drop between the batteryand the source side of the rear windowdefogger and record it here.

_______________ Volts

13. Look again at the voltage drop chart on page 4.Is this reading within specifications?


Rearwindowdefogger

–––––––––– +


Battery

6 Module 4

ECTC0016C

14. With the rear defogger circuit still operating,measure voltage drop across the entire rearwindow defogger grid and record the readinghere.

_______________ Volts

Note:Note:Note:Note:Note: Simply looking at the brightness of a bulb, orlistening to the speed of a motor, or feeling thewarmth of a defogger gird will not tell you ifany of these devices are operating as theynormally should. Now that you know thevoltage drop on the source side of the load aswell as the voltage drop through the load, theonly missing link is the ground side of thecircuit.

15. With the circuit still ON, connect the redmultimeter lead to the ground side of thedefogger grid and the black lead to the negativebattery cable. This connection will allow you tomeasure the voltage drop across the entireground circuit for the defogger grid.

The measured ground side voltage drop is:

_______________ Volts

Rearwindowdefogger

–––––––––– +


Battery

Rearwindowdefogger

–––––––––– +


Battery

7Module 4

Module 4

Note:Note:Note:Note:Note: A voltage drop measurement on the groundside of a circuit tests all of the following:

• Circuit connections within the wiringharness

• The connection at the body groundlocation for the defogger grid

• The frame of the vehicle• The battery ground cable• The connection at the battery post

Each of these listed points could be the rootcause of a voltage drop. The challenge is topinpoint the problem to the exact cause byfollowing a logical sequence of diagnosingeach part of the circuit and ruling out each partone at a time.

16. Now that you know the total voltage dropswithin the circuit, determine if anything couldhave been overlooked. Fill in the boxes below toverify the readings you just obtained.

NoteNoteNoteNoteNote: A weak battery or insufficiently charged batterywill affect the results of a voltage drop test.

8 Module 4

ECTC0016C

17. Now measure the available battery sourcevoltage and compare with the total voltagedrop measurements. Are they the same?


In summary, voltage drop testing is only partiallyeffective unless you have all of the facts. You mustknow the available battery voltage to begin with, soyou can compare all of the other voltage dropreadings to this total. Keeping in mind thespecifications in the chart at step 8, you should beable to determine if any of the readings are outsidethe normal operating range. By putting all these factstogether with a solid customer concern, you shouldbe able to effectively diagnose problems in faultycircuits.

You have just completed this worksheet. You shouldnow be able to measure voltage drop as specifiedand evaluate the results against establishedspecifications. If you have any doubt about your skillsin completing this worksheet, please return to step 1and review your work. Once you are confident ofyour skills, have your instructor verify your work.

Instructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s InitialsInstructor’s Initials _______________________

Return the workstation to the condition that youReturn the workstation to the condition that youReturn the workstation to the condition that youReturn the workstation to the condition that youReturn the workstation to the condition that youfound it.found it.found it.found it.found it.

1Module 5

Module 5

Objective:Objective:Objective:Objective:Objective: Given a digital multimeter, a circuitsimulator, a service manual, a fuel-injected vehicle and other components,measure resistance and compare tospecifications.

Relevance:Relevance:Relevance:Relevance:Relevance: Electrical resistance opposes the flowof current in a circuit. Electricalaccessories, also referred to as“loads”, use up most of the voltage in acircuit.

Excessive circuit resistance causes thecurrent flow to decrease. Thisresults in faulty circuit operation.

Resources:Resources:Resources:Resources:Resources: • Digital multimeter• Circuit simulator• Service Manual• Various electrical components• Fuel injected vehicle• Combination Switch

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Measure the resistance of variouselectrical components with a digitalmultimeter.

Check continuity of a combinationlighting switch.

MEASURING RESISTMEASURING RESISTMEASURING RESISTMEASURING RESISTMEASURING RESISTANCEANCEANCEANCEANCE

2 Module 5

ECTC0016C

1. Place the overlay for circuit #1 on thesimulator and build the circuit below. Do notconnect to the battery.

Overlay #1Overlay #1Overlay #1Overlay #1Overlay #1

Source wireSource wireSource wireSource wireSource wire

SwitchSwitchSwitchSwitchSwitch

2. Connect the test leads to the meter jacks andswitch the meter to “Ω.” Touch the test leadstogether and verify the readout is 0–0.3 Ohms(Continuity).

3. Measure the resistance of the source wire.Readings of less than 1 Ohm are an exception.

Note:Note:Note:Note:Note: When using digital multimeters with auto-ranging capabilities, the meter automaticallyselects the most accurate range when youturn it ON. Most auto-ranging meters allowyou to change the range or displayed valuewhile the meter is in use.

3Module 5

Module 5

4. Connect one of the ohmmeter leads to each ofthe switch terminals, then close the switch.

Note:Note:Note:Note:Note: Never use the ohmmeter to make any testswith power connected to the circuit beingtested.This could damage the meter and givefalse readings.

5. Record the resistance (Ohms) you measured instep 4 in the space at left.

Note:Note:Note:Note:Note: Switch contacts should have very lowresistance.

6. What would cause high resistance acrossswitch contacts?

___________________________________

7. Measure and record the resistance of thefollowing circuit components:

a. Description: Load Resistance (Bulb)

Record your answer in the space at left.

b. Description: Resistance Across the Wires.

Record your answer in the space at left.

8. Add the resistance values just taken (steps 5–7)and record your answer below. This is the totalcircuit resistance.

____________Ohms, Total circuit resistance.

RECORDANSWER

RECORDANSWER

RECORDANSWER

4 Module 5

ECTC0016C

9. Connect additional simulator wires to the loadand to the switch but do not connect to thebattery.

Measure the resistance, then record youranswer in the space provided at left.

10. Does this reading equal the value in step 8?


11. What could cause this reading to be differentthan the other reading?

___________________________________

___________________________________

___________________________________

12. Ask your instructor to assign a test vehicle forthe following exercises.

13. Measure the resistance of four injectors.

Record the resistance measurements below.

#1 _________

#2 _________

#3 _________

#4 _________

14. How would the engine run if the resistance ofeach injector was significantly different?

___________________________________

___________________________________

RECORDANSWER

RECORDANSWER

5Module 5

Module 5

StopStopStopStopStop

Instructor’s Initials ______________________Instructor’s Initials ______________________Instructor’s Initials ______________________Instructor’s Initials ______________________Instructor’s Initials ______________________

Have your instructor assign a vehicle for the followingsteps.

A

B

CLeft turn

OFF

2nd

ONOFF

FOG LAMP

1st

TURNRight turn

N OFF

INT

LO

HI

Wash

WIPER CONTROL

15. Using the vehicle service manual or ESM,complete the switch charts at left and bottomfor the combination lighting, wiper and fog lampswitch you're measuring.

Note:Note:Note:Note:Note: Depending on your vehicle, you may not use allchart positions.

16. Using the ohmmeter, check continuity for eachswitch position according to the charts. Recordyour results here. (Circle one)

Lighting switch: OKOKOKOKOK Not OKNot OKNot OKNot OKNot OK

Wiper switch: OKOKOKOKOK Not OKNot OKNot OKNot OKNot OK

Fog lamp switch: OKOKOKOKOK Not OKNot OKNot OKNot OKNot OK

Turn signal switch: OKOKOKOKOK Not OKNot OKNot OKNot OKNot OK

Lighting Switch*Lighting Switch*Lighting Switch*Lighting Switch*Lighting Switch*

OFF 1st 2nd

A B C A B C A B C

Wiper Switch*Wiper Switch*Wiper Switch*Wiper Switch*Wiper Switch*

OFF INT LO HI WASHWASHWASHWASHWASH

R N L

TTTTTurn Signal Switch*urn Signal Switch*urn Signal Switch*urn Signal Switch*urn Signal Switch*

OFF ON

Fog Lamp Switch*Fog Lamp Switch*Fog Lamp Switch*Fog Lamp Switch*Fog Lamp Switch*

6 Module 5

ECTC0016C

You have just completed this worksheet. You shouldnow be able to measure resistance and compare it tospecifications. If you have any doubt about your skillsin completing this worksheet please return to step 1and review your work. Once you are confident of yourskills, have your instructor verify your work.



1Module 6

Module 6

Objective:Objective:Objective:Objective:Objective: Given a digital multimeter, a circuit testkit with overlay #1, measure currentflow through a circuit and evaluate theresults.

Relevance:Relevance:Relevance:Relevance:Relevance: Current is the flow of electrons in acircuit. Amperage, the measurement ofcurrent flow in a circuit, is affected bythe resistance of the circuit load andthe voltage applied to the circuit.

Malfunctions such as low voltage,excessive circuit resistance or a faultycomponent reduce current flow whichresults in poor circuit operation.

Batteries, starter motors andalternators operate under high currentdemands. When you suspect one ofthese is malfunctioning, measure thecurrent flow in the circuit and compareit with specifications in the servicemanual.

One of the more commonly overlookedreasons for testing current flow is todetermine what causes a battery to godead overnight.

Resources:Resources:Resources:Resources:Resources: • Digital multimeter• Circuit Test Kit• Circuit Overlay #1

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Measure current flow in a circuit with amultimeter.

Measure parasitic load in a test vehiclebattery.

MEASURING CURRENTMEASURING CURRENTMEASURING CURRENTMEASURING CURRENTMEASURING CURRENT

2 Module 6

ECTC0016C

1. Follow the drawing on simulator overlay #1 anduse the components provided to build thecircuit. Switch the simulator ON to be sure theload works, then switch it OFF.

CAUTION:

Never attempt to measure current flow in excessNever attempt to measure current flow in excessNever attempt to measure current flow in excessNever attempt to measure current flow in excessNever attempt to measure current flow in excessof 10 amps. Yof 10 amps. Yof 10 amps. Yof 10 amps. Yof 10 amps. You could damage the meterou could damage the meterou could damage the meterou could damage the meterou could damage the meter(possibly beyond repair) or melt the 10A fuse.(possibly beyond repair) or melt the 10A fuse.(possibly beyond repair) or melt the 10A fuse.(possibly beyond repair) or melt the 10A fuse.(possibly beyond repair) or melt the 10A fuse.

TTTTTo prevent damage to the meter or its fuse, beo prevent damage to the meter or its fuse, beo prevent damage to the meter or its fuse, beo prevent damage to the meter or its fuse, beo prevent damage to the meter or its fuse, besure to connect the meter’s red test lead to thesure to connect the meter’s red test lead to thesure to connect the meter’s red test lead to thesure to connect the meter’s red test lead to thesure to connect the meter’s red test lead to the“10A“10A“10A“10A“10A””””” meter jack and the black test lead to the meter jack and the black test lead to the meter jack and the black test lead to the meter jack and the black test lead to the meter jack and the black test lead to the“COM” jack.“COM” jack.“COM” jack.“COM” jack.“COM” jack.

2. Disconnect the source wire from the load.

3. Connect the multimeter to the circuit as shownin the following illustration.

Overlay #1Overlay #1Overlay #1Overlay #1Overlay #1Switch in negative side of circuitSwitch in negative side of circuitSwitch in negative side of circuitSwitch in negative side of circuitSwitch in negative side of circuit

3Module 6

Module 6

4. Rotate the selector knob so the multimeter is inthe DC Amps position.

5. Press the switch on the circuit tester to activatethe circuit and record the amperage reading atleft.

6. Switch the simulator OFF, disconnect the meterleads from the circuit, then reconnect the circuitwiring and meter as illustrated below.

RECORDANSWER

7. Make sure the selector knob on the multimeter isstill in the DC Amps position.

4 Module 6

ECTC0016C

8. Switch the simulator and circuit ON and recordthe amperage reading at left

Note:Note:Note:Note:Note: The amperage measured in a series circuitshould be the same at any point in the circuit.

9. Were the two amperage readings taken in steps5 and 8 about the same?



RECORDANSWER

Measure Parasitic LoadMeasure Parasitic LoadMeasure Parasitic LoadMeasure Parasitic LoadMeasure Parasitic Load

Have your instructor assign a vehicle for the followingsteps.

10. Using an assigned vehicle, measure the parasiticload on a battery.

11. Check to see that all circuits and the ignitionswitch are OFF.

12. Disconnect the negative battery cable andconnect the multimeter in series between thebattery post and battery cable.

5Module 6

Module 6

13. With the meter still set up to read amperage,what is the reading?

__________________ A

Note:Note:Note:Note:Note: In most cases, parasitic draw should be lessthan 30 mA if the vehicle is operating normally.Readings in excess of that typically indicate aproblem.

On cars equipped with BCM, a momentaryhigh current drain above 150 mA will occur,but after 30 seconds, the reading should dropbelow 30 mA.

14. Switch the meter OFF, then disconnect it fromthe battery.

15. Reconnect the battery cable.

You have just completed this worksheet. You shouldnow be able to measure current flow through a circuitand evaluate the results. If you have any doubt aboutyour skills in completing this worksheet, please returnto step 1 and review your work. Once you areconfident of your skills, have your instructor verify yourwork.



6

NOTES

Module 6

1Module 7

Module 7

ObjectiveObjectiveObjectiveObjectiveObjective: Given a combination switch and acombination switch circuit, read acombination switch chart anddiagnose various combination switchcircuits using a digital multimeter.

Relevance:Relevance:Relevance:Relevance:Relevance: A combination switch contains multipleswitches. Each multiple switch uses asingle control lever to control severalcircuits.

In order to diagnose a malfunction inone or more related circuits you mustunderstand how the switch works andhow it controls the various circuits.

Resources:Resources:Resources:Resources:Resources: Combination light switch

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Identify the terminal contacts in acombination light switch.

Identify circuit connections and currentpaths in a lighting circuit.

COMBINACOMBINACOMBINACOMBINACOMBINATION SWITTION SWITTION SWITTION SWITTION SWITCH OPERACH OPERACH OPERACH OPERACH OPERATIONTIONTIONTIONTION

Sample Combination SwitchSample Combination SwitchSample Combination SwitchSample Combination SwitchSample Combination Switch

2 Module 7

ECTC0016C

Refer to Figure 1 and the switch chart for steps 1–3.

1. The combination switch (Figure 1) controls theparking lights, high and low beam headlamps,turn signals, windshield wipers and windshieldwasher. Study the switch chart at left andFigure 1.

How many light switch positions are there?

___________________________________

How many wiper positions are there?

___________________________________

2. There are two types of illustrations in the servicemanual that describe the operation of thecombination switch:

• Charts• Wiring Diagram

3. A Combination Switch Chart, like the one on theleft, illustrates the following:

• Terminal numbers• Switch positions• Continuity indicators (the lines between

circles)

Which terminals are connected when theswitch is positioned in 2B?

___________________________________


TURNRight turn

Left turn

OFF

INTWASH

HI

LOOFF2nd

C

B

AON

N

FOG LAMP

1st

SwitchPositions

Lineindicatescontinuity

Lighting Switch Chart, SampleLighting Switch Chart, SampleLighting Switch Chart, SampleLighting Switch Chart, SampleLighting Switch Chart, Sample

Connector (terminal) numbers

3Module 7

Module 7

The wiring diagrams on the following page (Figures 2and 3) illustrate the circuits attached to a hazardswitch. The light switch wiring diagrams showncontain the following information:

• Voltage source for the switch.

• Switch terminal numbers

• Wiring that connects the circuitcomponents.

Answer the following questions which refer to theelectrical diagrams on the following page (Figures 2and 3).

4. Which fuses connect the battery to the hazardswitch?

____________________________________

5. What are the connector numbers for the frontturn signal lamps?

____________________________________

6. Study Figures 2 and 3 on the following page.Based on these wiring diagrams, locate thehazard switch, then record the switch terminalnumbers for the circuits listed at left.

7. What is the harness connector number atthe hazard switch?

___________________________________

ComponentComponentComponentComponentComponent

Combination Flasher

Multi-Remote Control Relay-2

Turn Signal Lamp, RH

Combination Meter(Turn Signal Lamp), LH

Ignition Switch

Battery power

TTTTTerminalerminalerminalerminalerminal

4 Module 7

ECTC0016C

Figu

re 2

Figu

re 2

Figu

re 2

Figu

re 2

Figu

re 2

Figu

re 3

Figu

re 3

Figu

re 3

Figu

re 3

Figu

re 3

5Module 7

Module 7

8. Identify the harness connector numbers atthe rear turn signal lamps.

___________________________________

9. Identify and describe the fuses that protect theTurn Signal and Hazard Warning Lamp circuits.

___________________________________

___________________________________

Note:Note:Note:Note:Note: An electrical schematic does not show thedetail found in a “wiring diagram,” but theentire circuit is displayed on a single page.This avoids having to follow the circuit throughseveral pages to trace a circuit or a wire.

Not all electrical circuits have a schematicdiagram. For those that are available, they willhelp you understand how the circuit operates.A System Description usually accompaniesthe schematic to describe power distributionwithin the circuit.

6 Module 7

ECTC0016C

Answer the following questions about the Turn SignalCircuit using the Turn Signal Operation information andschematic diagram (Figure 4).

10. From the system description, identify which fusepowers the hazard switch:

#________ Fuse rating: _______A

11. From what terminal on the Combination FlasherUnit does current enter from the Hazardswitch?

Terminal ________

12. Identify the circuit path (in sequence) from thehazard switch to the rear combination lamp, LHand ground when the turn signal switch is in theLEFT TURN position.

Letter Part Name

____ ________________________

____ ________________________

____ ________________________

____ ________________________

____ ________________________

____ ________________________

____ ________________________

13. Starting from the LH front turn signal lamp,trace the circuit back to the source.

14. Identify the letter that indicates where the LHturn signal circuit becomes a parallel circuit.

_____________

7Module 7

Module 7


AAAAA

BBBBB CCCCC

EEEEE

FFFFF

MMMMM

LLLLL

DDDDD

IIIII

KKKKK

JJJJJ

NNNNN

GGGGG

HHHHH

OOOOO

8 Module 7

ECTC0016C

Use the wiring diagram on page 9 (Figure 5) toanswer the following questions:

15. What is the fuse number and rating for thecombination switch circuit?

#________ Fuse rating: _______A

16. What does the black dot at represent?

_________________________

17. Does receive “switched” power orconstant battery power?

____________________

18. How much voltage should be at in the“OFF” position?

_________________________

19. How much voltage should be at withthe ignition switch OFF?

_________________________

20. How much voltage should be with theFog Lamp Switch ON?

_________________________

21. What happens to the front fog lamps ifthere is an open circuit at ?

LH lamp__________________

RH lamp__________________

11111

22222

33333

44444

55555

66666

9Module 7

Module 7

11111

44444

22222

55555

66666

33333


10 Module 7

ECTC0016C

You have just completed this worksheet. You shouldnow be able to read a combination switch chart anddiagnose various combination switch circuits using adigital multimeter. If you have any doubt about yourskills in completing this worksheet please return tostep 1 and review your work. Once you are confidentof your skills, have your instructor verify your work.


Return the workstation to the condition in whichReturn the workstation to the condition in whichReturn the workstation to the condition in whichReturn the workstation to the condition in whichReturn the workstation to the condition in whichit was found.it was found.it was found.it was found.it was found.

1Module 8

Module 8

Objective:Objective:Objective:Objective:Objective: Given a service manual or ESM, adigital multimeter, a one transfer (1T)relay and circuit test kit w/overlay #2,diagnose the operation of a 1T relay.

Relevance:Relevance:Relevance:Relevance:Relevance: Unwanted circuit resistance can causeabnormal voltage drops. Abnormalvoltage drops can lead to customercomplaints relating to faulty circuitoperation.

Poor connections or corrosion may bethe root cause of the high resistance. Avoltmeter can be used to analyze thecircuit while in operation to help locatethe fault.

Resources:Resources:Resources:Resources:Resources: • Circuit Test Kit w/overlay #2• Digital Multimeter• 1T Relay

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Predict and measure available voltageat the terminals of a 1T relay.

DIAGNOSING ONE TRANSFER (1T) RELADIAGNOSING ONE TRANSFER (1T) RELADIAGNOSING ONE TRANSFER (1T) RELADIAGNOSING ONE TRANSFER (1T) RELADIAGNOSING ONE TRANSFER (1T) RELAY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONS

To hoodswitch

To starter circuit

From voltage source

Sample 1-Sample 1-Sample 1-Sample 1-Sample 1-T relayT relayT relayT relayT relay

2 Module 8

ECTC0016C

Predicted VPredicted VPredicted VPredicted VPredicted Voltageoltageoltageoltageoltage

1. Before you build the circuit shown on simulatoroverlay #2, predict the voltagepredict the voltagepredict the voltagepredict the voltagepredict the voltage level at each ofthe terminals.

Examine the top of the relay and the simulatoroverlay to identify the terminal numbers.

a. Assume the black lead of the multimeter isconnected to ground and the red leadtouches the terminals listed in the charts.

b. First, assume the coil control switch isOpenOpenOpenOpenOpen, then assume it is ClosedClosedClosedClosedClosed.

Record your predicted voltage readings in thecharts at left.

Terminal 1

Terminal 2

Terminal 3

Terminal 4

Terminal 5

Switch OpenSwitch OpenSwitch OpenSwitch OpenSwitch Open

A

B

C

D

E

Switch ClosedSwitch ClosedSwitch ClosedSwitch ClosedSwitch Closed

A

B

C

D

E

TTTTTest Pest Pest Pest Pest Pointointointointoint VVVVVoltage, predictedoltage, predictedoltage, predictedoltage, predictedoltage, predicted

Terminal 1

Terminal 2

Terminal 3

Terminal 4

Terminal 5

TTTTTest Pest Pest Pest Pest Pointointointointoint VVVVVoltage, predictedoltage, predictedoltage, predictedoltage, predictedoltage, predicted

Overlay #2Overlay #2Overlay #2Overlay #2Overlay #2

3Module 8

Module 8

Measured VMeasured VMeasured VMeasured VMeasured Voltageoltageoltageoltageoltage

2. Use the 1-Transfer Relay and the attachedjumper wires to build the circuit shown onoverlay #2.

3. Plug in the simulator and switch the circuit ON.Using the multimeter, measure and record thebattery voltage in the space at left.

4. Measure relay voltages on Circuit No. 2 asfollows:

Connect the black lead of the multimeter toground, then touch the red test lead to theharness side of each terminal and measure thevoltage.

a. Measure with the coil control switchswitchswitchswitchswitchopenopenopenopenopen.

b. Measure with the coil control switchswitchswitchswitchswitchclosedclosedclosedclosedclosed.

Record the readings at left.

Note:Note:Note:Note:Note: If a relay “buzzes,” current flow through the coilcontrol circuit may be too low to keep thecontact circuit closed. This failure occurs if thesource voltage is below specifications or if thecircuit resistance is too great. The coil controlwinding inside the relay should be the onlysignificant resistance in the circuit.

Terminal 1

Terminal 2

Terminal 3

Terminal 4

Terminal 5

a. Switch Opena. Switch Opena. Switch Opena. Switch Opena. Switch Open

A

B

C

D

E

b. Switch Closedb. Switch Closedb. Switch Closedb. Switch Closedb. Switch Closed

A

B

C

D

E

TTTTTest Pest Pest Pest Pest Pointointointointoint VVVVVoltage, measuredoltage, measuredoltage, measuredoltage, measuredoltage, measured

Terminal 1

Terminal 2

Terminal 3

Terminal 4

Terminal 5

TTTTTest Pest Pest Pest Pest Pointointointointoint VVVVVoltage, measuredoltage, measuredoltage, measuredoltage, measuredoltage, measured

RECORDANSWER

4 Module 8

ECTC0016C

5. Your voltage measurements should match thepredictions in step 1. If not, review yourpredictions and determine why you wereincorrect.

6. Examine the Antilock Brake System (ABS)circuit diagram (Figure 1) on the next page andanswer the following questions:

Two relays are illustrated in the circuit diagram.Which one is a 1T relay?

___________________________________

7. What type of relay is the other relay?

___________________________________

8. Which terminal of the IT relay provides sourcevoltage to the coil control circuit?

___________________________________

9. What terminal number of the ABS control unit isconnected to the source voltage of both relaycontrol coils?

___________________________________

5Module 8

Module 8

Ant

ilock

Bra

ke S

yste

m


6 Module 8

ECTC0016C

10. What must happen at terminal 6 of the ABSControl Unit so battery voltage is supplied tothe ABS solenoid valves? (Check one)

_____ Provide battery voltage to terminal 6.

_____ Provide ground at terminal 6.

Instructor’s Initials Instructor’s Initials Instructor’s Initials Instructor’s Initials Instructor’s Initials ______________________

Ask your instructor to assign you a test vehicle andcircuit.

Use the Starting System Simulator for the remainingsteps.

11. Verify relay operation by operating the circuit.

12. Remove the relay and use a voltmeter to test forvoltage at the coil control circuit, then recordthe voltage reading at left.

Note:Note:Note:Note:Note: A One Transfer Relay has a coil control circuitand two contact point circuits. Each circuitmust be diagnosed separately.

During diagnosis, remember to turn ON anyswitches required to operate the circuit.

Refer to the wiring diagram for the circuityou are testing.

13. If there is no voltage, diagnose the coil controlcircuit between the relay socket and the voltagesource. Refer to the wiring diagram and choosetest points that are easy to locate that will helpyou quickly isolate the problem.

RECORDANSWER

7Module 8

Module 8

14. Connect the red lead to the positive post of thebattery and touch the black lead to the controlcircuit ground terminal at the relay connectorsocket. If there is no ground at the socket themeter will read zero volts. If the meter reads12 volts, the control coil ground is good. Selecttest points that are easy to find and check, andlook for loose, dirty or damaged connections todetermine why the ground is faulty.

15. Use a fused jumper wire between terminal 3 and5 in the relay socket to test operation of thecircuit controlled by the relay.

Caution:

Never bypass the coil winding with a jumper.Doing so may damage the wiring harnessand/or control switches.

16. If the circuit does not work with the fusedjumper installed,

• there may be no source voltage at terminal #3

• there may be an open between terminal #5and the load.

• the ground for the load may be open.

17. Use the same procedure to test the normallyclosed contact point circuit by jumping terminals#3 and #4 at the relay socket.

Does the load in this circuit operate?


You have just completed this worksheet. You shouldnow be able to diagnose the operation of a onetransfer (1T) relay. If you have any doubt about yourskills in completing this worksheet please return tostep 1 and review your work. Once you are confidentof your skills, have your instructor verify your work.

Instructor’s Initials Instructor’s Initials Instructor’s Initials Instructor’s Initials Instructor’s Initials ______________________


8

NOTES

Module 8

1Module 9

Module 9

Objective:Objective:Objective:Objective:Objective: Given overlay #3, a service manual,and test equipment, test a vehicle witha 1M relay circuit.

Relevance:Relevance:Relevance:Relevance:Relevance: A one make (1M) relay contains a loadcircuit and a control circuit. The loadcircuit is completed when an externalswitch in the control circuit closes.

In the example, terminals 1 and 3 areconnected to source voltage.Terminal 5 connects to the load circuitand terminal 2 connects the controlcircuit to ground. When terminal 2 isgrounded, the contacts close,completing the circuit throughterminal 5 to the load.

Circuit malfunctions can be caused bya faulty relay, circuit wiring andconnectors or the actual load itself. Tobe effective at diagnosing 1M relaymalfunctions, you must understandrelay operation.

Resources:Resources:Resources:Resources:Resources: • Digital Multimeter• Simulator w/overlay #3• Service manual

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Use a multimeter to test the operationof a circuit controlled by a 1M relay.

DIAGNOSING ONE MAKE (1M) RELADIAGNOSING ONE MAKE (1M) RELADIAGNOSING ONE MAKE (1M) RELADIAGNOSING ONE MAKE (1M) RELADIAGNOSING ONE MAKE (1M) RELAY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONS

2 Module 9

ECTC0016C


1. Before you build the circuit shown on simulatoroverlay #3, predict the voltagepredict the voltagepredict the voltagepredict the voltagepredict the voltage levels at eachof the terminals.


Assume the black lead of the multimeter isconnected to ground and the red lead toucheseach test point listed in the chart. First, assumethe coil control switch is OPEN, then assume itis CLOSED.

Record the predicted voltage readings in thespaces provided at left.

TTTTTerminal 1erminal 1erminal 1erminal 1erminal 1





TTTTTest Pest Pest Pest Pest Pointointointointoint VVVVVoltage Predictedoltage Predictedoltage Predictedoltage Predictedoltage Predicted







A

B

C

D

A

B

C

D

Overlay #3

A

C

B

D

3Module 9

Module 9


2. Plug in the simulator, then measure andrecord the source voltage at left.

RECORDANSWER

3. Measure relay voltages as follows:

a. Use a 1 Make Relay to build the circuitshown on overlay #3. Attach the blackmultimeter lead to ground, then touchthe red lead to each of the numberedterminals.

b. Measure actual voltages at each of therelay terminals.

c. First, measure with the coil controlswitch OPEN, then measure with thecoil control switch CLOSED.

Record the measured voltage in thespaces provided.TTTTTerminal 1erminal 1erminal 1erminal 1erminal 1





TTTTTest Pest Pest Pest Pest Pointointointointoint VVVVVoltage Measuredoltage Measuredoltage Measuredoltage Measuredoltage Measured

A

B

C

D







A

B

C

D

4. Are the voltage measurements in step 3 thesame as your predictions in step 1?


4 Module 9

ECTC0016C

5. Refer to the Starting System Wiring Diagram(Figure 1) to answer the following questions.

Assume the ignition switch is in the STARTposition, the clutch interlock switch is in thereleased position, and the Theft Warning Relaycontrol circuit is not grounded. Record thevoltages you expect to measure at each of thetheft warning relay terminals.

6. Now, assume the ignition switch is in the STARTposition, the clutch interlock switch is stillreleased. Record the voltages you expect tomeasure at each of the clutch interlock relayterminals.

Diagnostic StrategyDiagnostic StrategyDiagnostic StrategyDiagnostic StrategyDiagnostic Strategy

After verifying a customer complaint (symptom), themost efficient way to diagnose relay circuitmalfunctions is to understand how the circuit shouldoperate.

• Check for voltage on both sides of eachfuse

• Locate and test for voltage at the circuitrelays and switches.

• Operate the circuit while touching and/orlistening to each relay in the circuit. Youshould be able to feel or hear the contactsclose.

• Substitute a known good battery andretest circuit operation.

• Look for loose ground connections.

7. As you have seen in this exercise, proper relayoperation is often affected by externalmalfunctions in the circuit. Don’t jump toconclusions.






Theft WTheft WTheft WTheft WTheft Warning Relayarning Relayarning Relayarning Relayarning Relay


1

2

3

4

5





Clutch Interlock RelayClutch Interlock RelayClutch Interlock RelayClutch Interlock RelayClutch Interlock Relay


1

2

3

5

5Module 9

Module 9


6 Module 9

ECTC0016C

8. Select one of the relay circuits at left to test onthe assigned vehicle:

Record the following information:

Vehicle model: ______________________

Vehicle year: _______________________

9. What system are you working on?

___________________________________

10. Refer to the wiring diagram for the circuit youare testing.

11. The coil control circuit and relay contact pointcircuits are two separate circuits. Diagnosethem separately.

12. The circuit must be ON to test for voltage.

13. To check operation of the contact circuit,connect a fused jumper wire to terminals #3 and#5 in the relay socket. These contacts normallyclose when the relay energizes. The load shouldoperate.

Does the load operate?


14. If the load does not operate, test for availablevoltage at terminal #3 in the relay socket, thenrecord the voltage reading at left.

15. If there is no voltage at terminal #3, test forvoltage at various places between the batteryand the relay. Use the wiring diagram to selectpoints that are easy to test to isolate themalfunction quickly.

Blower Motor Relay:Blower Motor Relay:Blower Motor Relay:Blower Motor Relay:Blower Motor Relay: Any VAny VAny VAny VAny Vehicleehicleehicleehicleehicle

Fuel Pump Relay:Fuel Pump Relay:Fuel Pump Relay:Fuel Pump Relay:Fuel Pump Relay: Any VAny VAny VAny VAny Vehicleehicleehicleehicleehicle

Ignition Relay:Ignition Relay:Ignition Relay:Ignition Relay:Ignition Relay: Any VAny VAny VAny VAny Vehicleehicleehicleehicleehicle

Radiator Fan Relays:Radiator Fan Relays:Radiator Fan Relays:Radiator Fan Relays:Radiator Fan Relays: Any VAny VAny VAny VAny Vehicleehicleehicleehicleehicle

RECORDANSWER

7Module 9

Module 9

16. Test for available voltage to the coil controlcircuit, then record the voltage reading at left.

17. If there is no voltage at the coil, test for voltageat various places between the battery and therelay. Use the wiring diagram to select pointsthat are easy to test to isolate the malfunctionquickly.

18. Connect the red meter lead to the positivebattery post and the black lead to the coilcontrol circuit ground terminal in the relaysocket.

19. What is the meter reading?

____________________________________

20. What does this indicate about the circuit?

___________________________________

Note:Note:Note:Note:Note: If the meter reading obtained is zero (0) volts,the circuit is open between the relay socketand ground. If the coil control ground iscomputer-controlled, switch the circuit ON toensure the control unit is trying to supplyground.

You have just completed this worksheet. You shouldnow be able to test a vehicle with a 1M relay circuit. Ifyou have any doubt about your skills in completingthis worksheet please return to step 1 and reviewyour work. Once you are confident of your skills, haveyour instructor verify your work.



RECORDANSWER

8

NOTES

Module xx

1Module 10

Module 10

Objective:Objective:Objective:Objective:Objective: Given a service manual, a digitalmultimeter, a Two Make (2M) relay anda circuit test kit with overlay #4,diagnose the operation of a 2M relay.

Relevance:Relevance:Relevance:Relevance:Relevance: A 2M relay contains two load circuitsand a control circuit. The load circuitsare completed when an external switchin the control circuit closes.

Circuit malfunctions can be caused bya faulty relay, circuit wiring andconnectors or the actual load itself. Tobe effective at diagnosing 2M relaycircuit faults, you must understandrelay operation.

Resources:Resources:Resources:Resources:Resources: • Digital multimeter• Assigned vehicle• Circuit Test Kit w/overlay #4• 2M Relay

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Use a multimeter to test the operationof a circuit controlled by a 2M relay.

DIAGNOSING TWO MAKE (2M) RELADIAGNOSING TWO MAKE (2M) RELADIAGNOSING TWO MAKE (2M) RELADIAGNOSING TWO MAKE (2M) RELADIAGNOSING TWO MAKE (2M) RELAY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONSY MALFUNCTIONS

to fuse#10

to fuse#4

to fuse#1

Sample 2M relaySample 2M relaySample 2M relaySample 2M relaySample 2M relay

2 Module 10

ECTC0016C


1. Before you build the circuit shown on simulatoroverlay #4, predict the terminal voltagespredict the terminal voltagespredict the terminal voltagespredict the terminal voltagespredict the terminal voltages in the2M relay circuit.


Assume the black lead of the multimeter isconnected to ground and the red lead toucheseach test point listed in the chart. First assumethe coil control switch is OPEN, then assume itis CLOSED.

Record the predicted voltage readings in thespaces provided.











TTTTTerminal3erminal3erminal3erminal3erminal3






A

B

C

D

E

F

A

B

C

D

E

F

Overlay #4 SchematicOverlay #4 SchematicOverlay #4 SchematicOverlay #4 SchematicOverlay #4 Schematic

A

C

D

EF

B

3Module 10

Module 10


2. Plug in the simulator, then measure and recordthe source voltage at left.

















A

B

C

D

E

F

A

B

C

D

E

F

RECORDANSWER

3. Measure relay voltages as follows:

a. Use a 2M Relay to build the circuitshown on the overlay.

b. Attach the black multimeter lead toground, then touch the red test lead toeach of the numbered terminals.

c. Measure actual voltages at each of therelay terminals.

d. First, measure with the coil controlswitch OPEN, then measure with thecoil control switch CLOSED.

Record the measured voltages in the spacesprovided.

4. Are the voltage measurements in step 3 thesame as your predictions in step 1?


4 Module 10

ECTC0016C

5. Answer the following questions about the2M Multi-Remote Control Relay-1 in the TurnSignal and Hazard Warning Lamp circuit(Figure 1).

Situation:When the hazard switch is ON (closed) thehazard lamps remain OFF. How can you test therelay to determine if the malfunction is in therelay coil circuit or the contact circuit? Selectthe best answer:

a. With the relay removed, connect afused jumper wire between relaysockets 3 and 5, then observe the turnsignal lamps. The left hand lampsshould illuminate.

b. With the relay removed, jumper relaysocket 6 and 7 and observe the turnsignal lamps. The right hand lampsshould illuminate.

c. With the relay removed, jumper relaysocket 1 and 2 and observe the lamp.

d. Choices a and b are both correct.

5Module 10

Module 10

Figure 1

6 Module 10

ECTC0016C

6. Answer the following questions using theattached Rear Window Defogger wiringdiagram (Figure 2) and the service manualdescription.

Identify the relay in the wiring diagram.

Relay name Type NO/NC Case color

__________________________________

7. The Smart Entrance Control Unit controls theground for the Rear Window Defogger Relay.Refer to the wiring diagram for this circuit andcheck all of the following that apply.

Assuming fuse #1 is good, voltage isavailable at terminal 11 at all timeswhen the ignition switch is ON.

On cars without power door locks,voltage to terminal 1 at the rearwindow defogger switch comes fromterminal 3 of the defogger timer.

If fuse #9 fails during operation of therear defogger, a 30 amp fuse should beused to replace it.

8. With the Rear Window Defogger Switch ON(closed), what should the voltage reading be atterminal 11 of the Smart Entrance Control Unit?

Battery voltage, 12 volts

Battery ground, 0 volts

9. With the Rear Window Defogger Switch ON(closed), what should the voltage reading be atterminal 20 of the Smart Entrance Control Unit?

Battery voltage, 12 volts

Battery ground, 0 volts

7Module 10

Module 10

Figu

re 2

8 Module 10

ECTC0016C

10. Based on the circuit in Figure 2, assume theignition switch and Defogger Switch are bothON. Record the voltages you expect to measureat each of the Defogger circuit terminals in thecharts at left.

11. What is the primary reason for using a 2M relayin the Defogger Circuit? (Circle one)

a. Due to the function of this circuit, thereis a need to control each circuitindependently. For example, power tothe indicator lamp can be controlledindependently by the defogger switch.

b. Due to the high current demandsplaced on this relay there is the dangerthat a single set of relay contacts mightbe damaged or burned.


Shop ExerciseShop ExerciseShop ExerciseShop ExerciseShop Exercise

Ask your instructor to assign you a test vehicle.

12. Select one of these relay circuits to test on theassigned vehicle.

• Rear Defogger relay

• Theft Warning relay



Smart Entrance Control UnitSmart Entrance Control UnitSmart Entrance Control UnitSmart Entrance Control UnitSmart Entrance Control Unit








Defogger RelayDefogger RelayDefogger RelayDefogger RelayDefogger Relay








Defogger SwitchDefogger SwitchDefogger SwitchDefogger SwitchDefogger Switch


9Module 10

Module 10

13. Record the following information:

Vehicle model: ______________________

Vehicle year: ________________________

14. Which of the above circuits did you select?

___________________________________

15. Refer to the wiring diagram for the circuit you aretesting.

16. Switch the circuit ON when diagnosing circuits.

17. Remove the relay from its connector and test foravailable voltage at the coil control circuitsocket. Record the voltage at left.

18. If there is no voltage at this location, test forvoltage at selected points between the batteryand relay. Use the wiring diagram to selectpoints that are easy to test in order to isolatethe problem quickly.

19. Switch the defogger ON.

20. Connect the red multimeter lead to the positivebattery post and the black lead to the coilcontrol circuit ground terminal to verify a goodground, then record the voltage reading:

___________________________________

Based on this reading, do you think the groundcircuit is good?

YES / NOYES / NOYES / NOYES / NOYES / NO (Circle One)

RECORDANSWER

10 Module 10

ECTC0016C

21. The 2M Relay has two contact circuits.

• To test them, remove the relay from thesocket and connect socket terminals#3 and #5 with a fused jumper lead.The load should operate.

• Jump terminals #6 and #7 with thefused jumper lead. The load shouldoperate.

22. If the load does not operate in either case, usethe wiring diagram to determine which terminalnumbers receive voltage for the contact circuits.Use the voltmeter to test for voltage at theterminals for the contact circuits in the relaysocket.

Record the readings in the space at left.

23. If voltage is not present, diagnose each contactcircuit between the relay socket and the voltagesource by testing for voltage at selected testpoints. Use the wiring diagram to select pointsthat are easy to test in order to isolate theproblem quickly.

You have just completed this worksheet. You shouldnow be able to diagnose the operation of a 2M relay.If you have any doubt about your skills in completingthis worksheet please return to step 1 and reviewyour work. Once you are confident of your skills, haveyour instructor verify your work.



RECORDANSWER

1Module 11

Module 11

Objective:Objective:Objective:Objective:Objective: Given a test kit with overlay #5, aservice manual, digital multimeter and aOne Make-One Break (1M-1B) Relay,diagnose the operation of a 1M-1Brelay.

Relevance:Relevance:Relevance:Relevance:Relevance: A One Make-One Break (1M-1B) relaycontains two load circuits and acontrol circuit. Each load circuit isalternately powered depending onwhether the control circuit is energizedor not.

Circuit malfunctions can be caused bya faulty relay, circuit wiring,connections or the load. To repair acircuit containing a 1M-1B relay youshould understand how this type ofrelay operates.

Resources:Resources:Resources:Resources:Resources: • Digital multimeter• Circuit Test Kit w/overlay #5• Test vehicle• 1M-1B relay• Starter simulator

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Use a multimeter to test the operationof a circuit controlled by a 1M-1B relay.

DIAGNOSING ONE MAKE-ONE BREAK (1M-1B)RELAY MALFUNCTIONS

Sample 1M-1B RelaySample 1M-1B RelaySample 1M-1B RelaySample 1M-1B RelaySample 1M-1B Relay

2 Module 11

ECTC0016C


1. Before you build the circuit shown on simulatoroverlay #5, predict the voltagepredict the voltagepredict the voltagepredict the voltagepredict the voltage levels at each ofthe terminals.


To do this, assume the black multimeter lead isconnected to ground and the red lead toucheseach of the test points to the left. First, assumethe coil control switch is open, then assume it isclosed.

















A

B

C

D

E

F

A

B

C

D

E

F

Overlay #5 SchematicOverlay #5 SchematicOverlay #5 SchematicOverlay #5 SchematicOverlay #5 Schematic

A

C

D

E

B

F

3Module 11

Module 11


2. Plug in the simulator, then measure and recordthe source voltage in the space at left.

















A

B

C

D

E

F

A

B

C

D

E

F

RECORDANSWER

3. Use the 1M-1B relay and build the circuit shownon overlay #5. Then attach the black meter leadto ground. Touch the red test lead to each of theterminals in the charts at left.

4. Measure relay voltages on Circuit No. 5 (1M-1BRelay) with the coil control switch open andrecord the readings at left.

5. Next, measure voltages with the coil controlswitch closed, then record the readings at left.

6. Are the measured readings the same as yourpredictions (step 1)?


4M

odule 11

EC

TC

0016C

SchematicFigure 1

E

D

CB

A

5Module 11

Module 11

7. Examine the Automatic Speed Control Device(ASCD) circuit diagram in figure 1 and answerthe following questions:

There are five relays in the circuit diagram. Usingthe text section as reference, record the nameand relay type (1T, 1M, 2T, etc.), whether it isNO or NC and the relay case color.

Relay nameRelay nameRelay nameRelay nameRelay name T T T T Type NO/NC Case colorype NO/NC Case colorype NO/NC Case colorype NO/NC Case colorype NO/NC Case color

E

D

C

B

A

8. Which position must the inhibitor switch be in toconnect source voltage (through the inhibitorrelay) to terminal 5 of the ASCD control unit?

___________________________________

___________________________________

9. Which relay connects the voltage source to thenormally closed contacts of the Inhibitor Relay?

___________________________________

___________________________________

10. Which ASCD Main Switch position is used tocomplete the circuit to the normally closedcontacts of the Inhibitor Relay?

OFF / ONOFF / ONOFF / ONOFF / ONOFF / ON (Circle one)

6 Module 11

ECTC0016C

11. Select the inhibitor relay to diagnose on the testvehicle.


12. Ask your instructor to assign you a test vehicleand circuit.

13. Check the operation of the load controlled bythis relay. Does the load operate?

YES / NOYES / NOYES / NOYES / NOYES / NO (Circle One)

14. If the load does not operate, remove the relayand test for available voltage at terminal 1 in therelay socket and record the reading at left.

15. If there is no voltage, test for voltage at differentpoints between the source and the controlcircuit. Using the wiring diagram, locate themost efficient test points.

Note:Note:Note:Note:Note: Diagnose malfunctions in the control coilground circuit:Using an ohmmeter -

An ohmmeter checks the continuity ofthe circuit.

Using a voltmeter -A voltmeter tests for voltage atdifferent points in the circuit while it isoperating. While the circuit isgrounded, there should be almost zerovolts.

RECORDANSWER

7Module 11

Module 11

RECORDANSWER

16. If there is voltage at terminal #1, use a fusedjumper between socket terminal 6 and 7 and tryto operate the load again.

Does the load in this circuit operate?


17. If the load still does not operate, test for voltageat the terminals for the contact point circuit inthe relay socket. Use the wiring diagram todetermine which terminals should be connectedto source voltage.

Record the meter readings in the spaceprovided at left.

18. If there is no voltage available, test for voltage atpoints that are easy to locate to help you quicklyisolate the problem.

You have just completed this worksheet. You shouldnow be able to diagnose the operation of a1M-1B relay. If you have any doubt about your skills incompleting this worksheet please return to step 1and review your work. Once you are confident of yourskills, have your instructor verify your work.



8

NOTES

Module xx

1Module 12

Module 12

Objective:Objective:Objective:Objective:Objective: Given a customer’s repair order, aservice manual and a digital multimeter,verify, isolate, repair and recheck thefault in question.

Relevance:Relevance:Relevance:Relevance:Relevance: Circuit diagnosis is a critical part ofmaking effective repairs. In this exerciseyou will be given a customer concern.The symptom applies to a vehiclewhich you must repair. You must verify,isolate, repair and recheck the cause ofthe malfunction using the customerrepair order, vehicle service manual,appropriate test equipment, and alldiagnosis skills.

Resources:Resources:Resources:Resources:Resources: • Assigned vehicle• Electronic Service Manual• Digital Multimeter

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Vehicle electrical fault repaired andcircuit operation verified by instructorafter repair. When performingdiagnostic procedures the followingitems should always be followed:

1. Verify the complaint2. Isolate the cause3. Repair the fault4. Recheck your repair

CIRCUIT DIAGNOSIS EXERCISE: #1

2 Module 12

ECTC0016C

Customer Concern:Customer Concern:Customer Concern:Customer Concern:Customer Concern:

“Engine overheats. Customer uses A/C, engine overheats quickly when“Engine overheats. Customer uses A/C, engine overheats quickly when“Engine overheats. Customer uses A/C, engine overheats quickly when“Engine overheats. Customer uses A/C, engine overheats quickly when“Engine overheats. Customer uses A/C, engine overheats quickly whenoutside temp. is hot”outside temp. is hot”outside temp. is hot”outside temp. is hot”outside temp. is hot”

Cause:Cause:Cause:Cause:Cause:

Corrective Action:Corrective Action:Corrective Action:Corrective Action:Corrective Action:


3Module 12

Module 12

1. Record the following information here and onthe repair order (figure 1).

Vehicle model: ______________________

Model year: ________________________

2. Background information for Diagnosis #1:

Customer Concern:Customer Concern:Customer Concern:Customer Concern:Customer Concern: Engine overheats

Repair History:Repair History:Repair History:Repair History:Repair History:On 7/5, thermostat was replaced, but repairswere not verified.

On 7/8, the radiator cap was replaced andcoolant level topped off.

Car was towed in two days later for samesymptom.

3. With a teammate, think of all the possibilities forthis incident. On the following page, list all of thepossible causes for this overheating condition. Ifyou have difficulty recalling all of the possiblecauses, you may use any diagnostic resourceswithin the classroom to help you build your list.Once your list is complete to your satisfaction,rank the causes in the order of most probable. Inother words, number them in the order youwould test them.

4 Module 12

ECTC0016C

Possible Causes (List all possible causes forthe given symptoms)

________________________________________

________________________________________

________________________________________

________________________________________

________________________________________

________________________________________

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________________________________________

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________________________________________

5Module 12

Module 12

4. After completing step 3, discuss your strategywith the instructor.

5. With the instructor’s approval, verify, isolate,repair and recheck the fault in the order youranked them in step 3. Perform all testsnecessary to verify each possible cause.

6. During your diagnosis, list below the results ofyour findings for each of the items you checkfrom the list you created.

Item tested: Actual vehicle results:

1st _____________________________

2nd _____________________________

3rd _____________________________

Additional items tested:

________________________________

________________________________

________________________________

________________________________

________________________________

________________________________

________________________________

7. When you have repaired the problem on thevehicle and verified the repair, record the causeand corrective action on the repair order(page 2).

6 Module 12

ECTC0016C

As a result of this exercise, you should see the needfor effective diagnostic skills and the benefit of takingyour time to follow repair procedures and get theproblem resolved before returning the vehicle to thecustomer.

You have just completed this worksheet. You shouldnow be able to verify, isolate, repair and recheck thefault in question. If you have any doubt about yourskills in completing this worksheet please return tostep 1 and review your work. Once you are confidentof your skills, have your instructor verify your work.



1Module 13

Module 13







2 Module 13

ECTC0016C





3Module 13

Module 13

1. Record the following information here and onthe repair order (Figure 1).

Vehicle model: ______________________

Model year: ________________________


Customer Concern:Customer Concern:Customer Concern:Customer Concern:Customer Concern:Customer claims that it takes a long time toclear the rear window using the defogger circuit.

Repair History:Repair History:Repair History:Repair History:Repair History:Checked voltage drop across rear window grid.Voltage appeared to be in the normal range.

Replaced rear window defogger relay, but didnot validate the repair.

3. With a teammate, think of all the possibilities forthis incident. On the following page, list all of thepossible causes for this defogging condition. Ifyou have difficulty recalling all of the possiblecauses, you may use any diagnostic resourceswithin the classroom to help you build your list.Once your list is complete to your satisfaction,rank the causes in the order of most probable. Inother words, number them in the order youwould test them.

4 Module 13

ECTC0016C


________________________________________

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________________________________________

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________________________________________

________________________________________

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________________________________________

5Module 13

Module 13





1st _____________________________

2nd _____________________________

3rd _____________________________


________________________________

________________________________

________________________________

________________________________

________________________________

________________________________

________________________________


6 Module 13

ECTC0016C





1Module 14

Module 14







2 Module 14

ECTC0016C





3Module 14

Module 14


Vehicle model: ______________________

Model year: ________________________



___________________________________

___________________________________

___________________________________

Repair History:Repair History:Repair History:Repair History:Repair History:

___________________________________

___________________________________

___________________________________

3. With a teammate, think of all the possibilities forthis incident. On the following page, list all of thepossible causes for this condition. If you havedifficulty recalling all of the possible causes, youmay use any diagnostic resources within theclassroom to help you build your list. Once yourlist is complete to your satisfaction, rank thecauses in the order of most probable. In otherwords, number them in the order you would testthem.

4 Module 14

ECTC0016C


________________________________________

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________________________________________

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________________________________________

5Module 14

Module 14





1st _____________________________

2nd _____________________________

3rd _____________________________


________________________________

________________________________

________________________________

________________________________

________________________________

________________________________

________________________________


6 Module 14

ECTC0016C





1Module 15

Module 15







2 Module 15

ECTC0016C





3Module 15

Module 15


Vehicle model: ______________________

Model year: ________________________



___________________________________

___________________________________

___________________________________


___________________________________

___________________________________

___________________________________


4 Module 15

ECTC0016C


________________________________________

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5Module 15

Module 15





1st _____________________________

2nd _____________________________

3rd _____________________________


__ _____________________________

________________________________

________________________________

________________________________

________________________________

________________________________

________________________________


6 Module 15

ECTC0016C





1Module 16

Module 16







2 Module 16

ECTC0016C





3Module 16

Module 16


Vehicle model: ______________________

Model year: ________________________



___________________________________

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___________________________________

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4 Module 16

ECTC0016C


________________________________________

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5Module 16

Module 16





1st _____________________________

2nd _____________________________

3rd _____________________________


________________________________

________________________________

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________________________________

________________________________

________________________________

________________________________


6 Module 16

ECTC0016C





1Module 17

Module 17







2 Module 17

ECTC0016C





3Module 17

Module 17


Vehicle model: ______________________

Model year: ________________________



___________________________________

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4 Module 17

ECTC0016C


________________________________________

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5Module 17

Module 17





1st _____________________________

2nd _____________________________

3rd _____________________________


________________________________

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6 Module 17

ECTC0016C





1Module 18

Module 18

Objective:Objective:Objective:Objective:Objective: Given a digital multimeter, electricalcomponents and a car, identify thedifferent meter features, connect thetest leads, and perform voltage,resistance, amperage and continuitytests.

Relevance:Relevance:Relevance:Relevance:Relevance: A digital multimeter is an importanttool to diagnose electricalmalfunctions. It can measure voltage,voltage drop, current, resistance andcheck continuity. A high impedancedigital multimeter should be used totest automotive electrical circuits.

Resources:Resources:Resources:Resources:Resources: • Digital Multimeter• Spark plug wire• AA battery• Paper clip• Assigned vehicle• Coolant temperature sensor• Fuel tank sending unit• Fuel injector• Wrapped harness• Good fuse• Faulty fuse• 1M relay with faulty coil circuit

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Prepare and connect a digitalmultimeter to measure voltage,resistance, amperage and continuity.

HOW THOW THOW THOW THOW TO USE A DIGITO USE A DIGITO USE A DIGITO USE A DIGITO USE A DIGITAL MULAL MULAL MULAL MULAL MULTIMETERTIMETERTIMETERTIMETERTIMETER

2 Module 18

ECTC0016C

Safety Information:Safety Information:Safety Information:Safety Information:Safety Information:

CAUTION:CAUTION:CAUTION:CAUTION:CAUTION:Never use the meter if the meter or testNever use the meter if the meter or testNever use the meter if the meter or testNever use the meter if the meter or testNever use the meter if the meter or testleads look damagedleads look damagedleads look damagedleads look damagedleads look damaged

Be sure the test leads and switch are in theBe sure the test leads and switch are in theBe sure the test leads and switch are in theBe sure the test leads and switch are in theBe sure the test leads and switch are in thecorrect position for the desiredcorrect position for the desiredcorrect position for the desiredcorrect position for the desiredcorrect position for the desiredmeasurement.measurement.measurement.measurement.measurement.

Never measure resistance in a circuit whenNever measure resistance in a circuit whenNever measure resistance in a circuit whenNever measure resistance in a circuit whenNever measure resistance in a circuit whenpower is applied.power is applied.power is applied.power is applied.power is applied.

Never touch the probes to a voltage sourceNever touch the probes to a voltage sourceNever touch the probes to a voltage sourceNever touch the probes to a voltage sourceNever touch the probes to a voltage sourcewhen the test leads are plugged into thewhen the test leads are plugged into thewhen the test leads are plugged into thewhen the test leads are plugged into thewhen the test leads are plugged into the10A or 300 mA input jack.10A or 300 mA input jack.10A or 300 mA input jack.10A or 300 mA input jack.10A or 300 mA input jack.

Never apply more than the rated voltageNever apply more than the rated voltageNever apply more than the rated voltageNever apply more than the rated voltageNever apply more than the rated voltagebetween any input jack and earth ground.between any input jack and earth ground.between any input jack and earth ground.between any input jack and earth ground.between any input jack and earth ground.

Be careful when working with voltagesBe careful when working with voltagesBe careful when working with voltagesBe careful when working with voltagesBe careful when working with voltagesabove 60 VDC or 30 Vabove 60 VDC or 30 Vabove 60 VDC or 30 Vabove 60 VDC or 30 Vabove 60 VDC or 30 VAC. Such voltagesAC. Such voltagesAC. Such voltagesAC. Such voltagesAC. Such voltagespose a shock hazard.pose a shock hazard.pose a shock hazard.pose a shock hazard.pose a shock hazard.

Keep your fingers behind the finger guardsKeep your fingers behind the finger guardsKeep your fingers behind the finger guardsKeep your fingers behind the finger guardsKeep your fingers behind the finger guardson the test probes when makingon the test probes when makingon the test probes when makingon the test probes when makingon the test probes when makingmeasurements.measurements.measurements.measurements.measurements.

WWWWWARNING:ARNING:ARNING:ARNING:ARNING:TTTTTO AO AO AO AO AVOID FVOID FVOID FVOID FVOID FALSE READINGS, WHICHALSE READINGS, WHICHALSE READINGS, WHICHALSE READINGS, WHICHALSE READINGS, WHICHCOULD LEAD TCOULD LEAD TCOULD LEAD TCOULD LEAD TCOULD LEAD TO POSSIBLE ELECTRICALO POSSIBLE ELECTRICALO POSSIBLE ELECTRICALO POSSIBLE ELECTRICALO POSSIBLE ELECTRICALSHOCK OR PERSONAL INJURSHOCK OR PERSONAL INJURSHOCK OR PERSONAL INJURSHOCK OR PERSONAL INJURSHOCK OR PERSONAL INJURYYYYY, REPLACE, REPLACE, REPLACE, REPLACE, REPLACETHE BATHE BATHE BATHE BATHE BATTERTTERTTERTTERTTERY AS SOON AS THE BAY AS SOON AS THE BAY AS SOON AS THE BAY AS SOON AS THE BAY AS SOON AS THE BATTERTTERTTERTTERTTERYYYYYINDICAINDICAINDICAINDICAINDICATTTTTOROROROROR( ) APPEARS.( ) APPEARS.( ) APPEARS.( ) APPEARS.( ) APPEARS.

Rotary Switch

Display

Input Jacks

Push Button(location mayvary)

Bar Graph

Input Jacks

TestSelections

Press andhold 2 sec.while turningmeter ON

POWER-ON OPTION: © AUTOMATIC TOUCH HOLDPOWER-ON OPTION: © AUTOMATIC TOUCH HOLDPOWER-ON OPTION: © AUTOMATIC TOUCH HOLDPOWER-ON OPTION: © AUTOMATIC TOUCH HOLDPOWER-ON OPTION: © AUTOMATIC TOUCH HOLDPRESS WHILE TURNING METER ONPRESS WHILE TURNING METER ONPRESS WHILE TURNING METER ONPRESS WHILE TURNING METER ONPRESS WHILE TURNING METER ON

WARNING WARNING WARNING WARNING WARNINGTO AVOID ELECTRICAL SHOCK REMOVE TESTTO AVOID ELECTRICAL SHOCK REMOVE TESTTO AVOID ELECTRICAL SHOCK REMOVE TESTTO AVOID ELECTRICAL SHOCK REMOVE TESTTO AVOID ELECTRICAL SHOCK REMOVE TEST

LEADS BEFORE OPENING CASE.LEADS BEFORE OPENING CASE.LEADS BEFORE OPENING CASE.LEADS BEFORE OPENING CASE.LEADS BEFORE OPENING CASE.TO PREVENT FIRE INSTALL FUSESTO PREVENT FIRE INSTALL FUSESTO PREVENT FIRE INSTALL FUSESTO PREVENT FIRE INSTALL FUSESTO PREVENT FIRE INSTALL FUSES

WITH AMP/VOLT RATINGS SHOWN.WITH AMP/VOLT RATINGS SHOWN.WITH AMP/VOLT RATINGS SHOWN.WITH AMP/VOLT RATINGS SHOWN.WITH AMP/VOLT RATINGS SHOWN.630mA 250V FAST630mA 250V FAST630mA 250V FAST630mA 250V FAST630mA 250V FAST

3A 600V FAST3A 600V FAST3A 600V FAST3A 600V FAST3A 600V FAST

NEDA 1604 9V 6F22 9VNEDA 1604 9V 6F22 9VNEDA 1604 9V 6F22 9VNEDA 1604 9V 6F22 9VNEDA 1604 9V 6F22 9V+–

WARNING WARNING WARNING WARNING WARNING10A RANGE UNFUSED. TO AVOID DAMAGE OR10A RANGE UNFUSED. TO AVOID DAMAGE OR10A RANGE UNFUSED. TO AVOID DAMAGE OR10A RANGE UNFUSED. TO AVOID DAMAGE OR10A RANGE UNFUSED. TO AVOID DAMAGE OR

INJURY USE ONLY IN PROTECTEDINJURY USE ONLY IN PROTECTEDINJURY USE ONLY IN PROTECTEDINJURY USE ONLY IN PROTECTEDINJURY USE ONLY IN PROTECTEDCIRCUITS WHICH CAN NOT EXCEEDCIRCUITS WHICH CAN NOT EXCEEDCIRCUITS WHICH CAN NOT EXCEEDCIRCUITS WHICH CAN NOT EXCEEDCIRCUITS WHICH CAN NOT EXCEEDEITHER 20 AMPS OR 4000 VOLT-AMPSEITHER 20 AMPS OR 4000 VOLT-AMPSEITHER 20 AMPS OR 4000 VOLT-AMPSEITHER 20 AMPS OR 4000 VOLT-AMPSEITHER 20 AMPS OR 4000 VOLT-AMPS

3Module 18

Module 18

Digital Multimeter Display SymbolsDigital Multimeter Display SymbolsDigital Multimeter Display SymbolsDigital Multimeter Display SymbolsDigital Multimeter Display Symbols

Digital Multimeter SymbolsDigital Multimeter SymbolsDigital Multimeter SymbolsDigital Multimeter SymbolsDigital Multimeter Symbols

Touch hold ON

Negative polarity(switch meter leads when this is displayed)

Bar graph of meter reading

Over Limits(The reading is out of the range of the meter’scapability. Usually means OPEN circuit)

Mega (1 million)

kilo (1 thousand)

Symbol DescriptionSymbol DescriptionSymbol DescriptionSymbol DescriptionSymbol Description

MMMMM

kkkkk

AAAAA

VVVVV

VVVVV

AAAAA

) ) )) ) )) ) )) ) )) ) ))))))

Alternating Current (AC)

Volts AC (VAC)

Amps AC

Direct Current (DC)

Volts DC (VDC)

Amps, DC

Ohms (resistance)

DC Volts less than 300mV

Diode

Audible Continuity

Important safety information

Ground

Meter fuse

Double Insulation

9V battery

Symbol DescriptionSymbol DescriptionSymbol DescriptionSymbol DescriptionSymbol Description

ΩΩΩΩΩ300mV300mV300mV300mV300mV

4 Module 18

ECTC0016C

Rotary Switch

1. To switch the meter ON, rotate the meter switch(left illustration) from OFF to another setting.

Each switch setting has only one function.Identify the switch functions by filling in thecorrect letter for each function:

____ Amps, AC

____ Ohms resistance

____ Volts, DC

____ Diode/Continuity

____ Volts, AC

____ Amps, DC

____ DC volts, 300 mV or less

A

B

C

D

E

FG

5Module 18

Module 18

Input Jacks

2. The meter has four (4) input jacks (leftillustration). Both amperage jacks (A & B) areinternally fused.

WARNING:

NEVER ATTEMPT A VOLTAGEMEASUREMENT IF A TEST LEAD IS IN THE10A JACK (B). YOU MIGHT BE INJURED ORDAMAGE THE METER.

Identify the input jack which corresponds to thefollowing switch positions:

____ Volts, Ohms, Diode Test and Continuity

____ Common (return) for Volts, Ohms,Diode Test and Continuity

____ Amps (10 A continuous)

____ Amps (less than 300 mA current)

Note:Note:Note:Note:Note: Red is the electrical color code for positive(+). Therefore, insert the red test lead into thejack labeled V (CCCCC). To measure current, usethe jack labeled 10A (AAAAA).

Only use the jack labeled “300mA” (AAAAA) tomeasure circuit current that is less than300mA.

Black is the electrical color code fornegative(–). Insert the black test lead into the jacklabeled COM (DDDDD).

BBBBB CCCCC

AAAAA DDDDD

10A10A10A10A10A

300300300300300mAmAmAmAmA

COMCOMCOMCOMCOM

FUSEDFUSEDFUSEDFUSEDFUSED

1000V1000V1000V1000V1000V750V750V750V750V750V

6 Module 18

ECTC0016C

Display

3. Readings appear on a liquid crystal display(LCD). See the figure below.

The symbols on the display indicate meterstatus (see chart on left).

ACDCV

kMm

Symbol MeaningSymbol MeaningSymbol MeaningSymbol MeaningSymbol Meaning

Alternating current or voltageDirect current or voltageVoltsManual range or Touch Hold ONOhmskilo, Units x 1,000Mega, Units x 1,000,000Milli, Units x 1/1000

Digital segments

Bar graph

Volts AC

M (Mega)/k (kilo) ohms

Volts DC

Low battery

Floating decimal locations

Touch Hold-ON ormanual mode

Polarity incorrect

4. The bar graph shows readings relative to the fullscale range. The bar graph lengthens as themeasurement value increases.

5. When switched from OFF to any position, thisbar graph display appears for 1 second as partof a self-test. The meter is now ready to take ameasurement.

Note:Note:Note:Note:Note: If a measurement is too large to be displayed,the letters “OL” (over limit) are displayed.

6. While the meter is in use, this symbol ( )appears to show approximately 8 more hours ofbattery life.

+++++–––––

7Module 18

Module 18

Using the Multimeter

7. Verify both meter leads are connected to theinput jacks (See the note on the bottom of page5 if you are unsure).

8. Rotate the meter switch to display resistance( ).

On the illustration at left, record the meterdisplay.

What does this measurement indicate?

____________________________________

9. Now touch the leads together. Record thereading at left.

Note:Note:Note:Note:Note: If the meter reading displays very lowresistance (<.5 ), the meter leads are in goodcondition.

10. Switch the meter OFF.

8 Module 18

ECTC0016C

Touch Hold Mode

11. Press and hold the pushbutton while rotatingthe switch to measure DC voltage.

Note:Note:Note:Note:Note: The manual range mode symbol appears onthe display along with the measurement mode(V, A, , etc.).

12. Measure the voltage of a flashlight battery usingthe meter test leads. Record the battery voltageat left.

13. What happens to the display when you removethe leads from the battery?

____________________________________

____________________________________

14. To exit the “Touch Hold” function, press thebutton.

Note:Note:Note:Note:Note: The meter beeps when Touch Hold isupdated. If you press the button again, themeter goes back into Touch Hold mode.

To exit Touch Hold completely, switch themeter OFF, then back ON.

Standby (Sleep) Mode

15. If the meter is ON but the rotary switch or thepushbutton is not used for 60 minutes (20minutes in diode test mode), the display goesblank except for four bar graph segments. Thisextends battery life.

Press and holdwhile selecting

measurement

Manual Range symbol

9Module 18

Module 18

How to Measure Resistance

16. Verify the test leads are in the and COMjacks.

17. Rotate the meter switch to .

18. Obtain the parts below from the instructor tomeasure resistance with the multimeter.

Use the meter leads to measure the resistanceof each part. Make sure you have a goodcontact between the probes and the devicebeing tested. Dirt, oil or other foreign matteraffects the resistance reading.

Note:Note:Note:Note:Note: Remember not to touch the test leads withyour fingers. This can affect the accuracy ofthe resistance readings.

Spark plug wire ____

Coolant temperature Sensor ____

Fuel tank sending unit, full tank ____

Fuel tank sending unit, empty tank ____

Throttle position sensor ______-_______

Note:Note:Note:Note:Note: The resistance in the meter test leads is about0.1 to 0.2 . When the resistance is less than1 ohm, subtract this from the display reading.

Measuring Resistance with a MultimeterMeasuring Resistance with a MultimeterMeasuring Resistance with a MultimeterMeasuring Resistance with a MultimeterMeasuring Resistance with a Multimeter

Red

Black

Radiator

Temperature sensor

COM

V

10 Module 18

ECTC0016C

How to Measure Voltage

19. Insert the test leads into the and COM jacks(see the illustration at left).

20. Rotate the meter switch to “V ”.

WARNING:

NEVER ATTEMPT A VOLTAGEMEASUREMENT WITH A TEST LEAD IN THE10A INPUT JACK. YOU MIGHT BE INJUREDOR DAMAGE THE METER.

Go to an assigned vehicle in the shop.

21. Switch the vehicle lights ON for 1 minute tobleed off surface charge from the battery, thenswitch them OFF.

22. Touch the probes to the battery terminals asshown, in parallel with the circuit. Voltage mustbe measured with the meter connected inparallel with the circuit.

23. Read the voltage. If you reverse the probes, thedisplay indicates negative polarity with a minussign (–).

Note:Note:Note:Note:Note: This no-load voltage measurement onlyindicates the state of charge, not the conditionof the battery.

Based on the meter display and thespecifications at left, what is the battery’s stateof charge?

________ %

A fully charged battery typically showsabout 12.6V.

Voltage % Charge12.60V 10012.45V 7512.30V 5012.15 25

Measuring VMeasuring VMeasuring VMeasuring VMeasuring Voltage with a Multimeteroltage with a Multimeteroltage with a Multimeteroltage with a Multimeteroltage with a Multimeter

Light Circuit

Red

Black

Relay

–+

300 m300 m300 m300 m300 m

11Module 18

Module 18

How to Test Continuity

24. Switch all circuits OFF. Verify the ignition switchis OFF.

25. Insert the test leads into the Ω and COM jacks.

26. Rotate the meter switch to “ ”.

27. Test the continuity of the following items on thebench:

Fuse 1 Continuity: YES / NOYES / NOYES / NOYES / NOYES / NO

Fuse 2 Continuity: YES / NOYES / NOYES / NOYES / NOYES / NO

1M Relay(control circuit) Continuity: YES / NOYES / NOYES / NOYES / NOYES / NO

Wrapped harness Continuity: YES / NOYES / NOYES / NOYES / NOYES / NOwire color _______ YES / NOYES / NOYES / NOYES / NOYES / NOwire color _______ YES / NOYES / NOYES / NOYES / NOYES / NOwire color _______ YES / NOYES / NOYES / NOYES / NOYES / NOwire color _______ YES / NOYES / NOYES / NOYES / NOYES / NOwire color _______ YES / NOYES / NOYES / NOYES / NOYES / NO

Note:Note:Note:Note:Note: Continuity exists if resistance is less thanabout 30 and the beeper sounds acontinuous tone.

Checking Switch Continuity with aChecking Switch Continuity with aChecking Switch Continuity with aChecking Switch Continuity with aChecking Switch Continuity with aMultimeterMultimeterMultimeterMultimeterMultimeter

Red

Black

COM

V

Female connector(disconnected)

Stoplight switch

300 m

–+

Brake pedal

12 Module 18

ECTC0016C

Quick Check of Internal Fuses

28. Insert one test lead in the V jack.

29. Rotate the switch to .

30. Touch the probe to the 300 mA jack (A) andread the display. Is the fuse good?


31. Touch the probe to the 10A jack (B) and readthe display. Is this fuse good?


(A) 4-8(A) 4-8(A) 4-8(A) 4-8(A) 4-8

(B)(B)(B)(B)(B)

(A)(A)(A)(A)(A)

06.006.006.006.006.0 OLOLOLOLOL

OKOKOKOKOK OKOKOKOKOK

(B) 0.1-0.2(B) 0.1-0.2(B) 0.1-0.2(B) 0.1-0.2(B) 0.1-0.2

13Module 18

Module 18

How to Measure Current

WARNING:

TURN POWER OFF BEFORE CUTTING,UNSOLDERING OR DISCONNECTING THECIRCUIT.

ALWAYS USE INDUCTIVE CURRENT CLAMP-ON PROBES IN CIRCUITS WHERE THEAMPERAGE EXCEEDS 10 A.

32. Switch all circuits OFF, then identify and removethe fuse for the dome light circuit.

33. Insert the test leads into the 10A and COMjacks.

34. Rotate the meter switch to “A ”.

35. Connect the red test lead to one fuse terminaland the black lead to the other fuse terminal.

Note:Note:Note:Note:Note: The meter can be connected to any convenienttest point in a circuit.

This places the meter in series with the circuitto test and all current will flow through themeter.

Always measure current with the meter inseries with the circuit being tested.

36. Switch the dome lamp ON, then read the meterdisplay and record the reading.

_________________ Amps

Measuring Current with a MultimeterMeasuring Current with a MultimeterMeasuring Current with a MultimeterMeasuring Current with a MultimeterMeasuring Current with a Multimeter

Red

Black

COM

V10A

Fuse Box

14 Module 18

ECTC0016C

Note:Note:Note:Note:Note: If the display shows a minus sign (–) to the leftof the reading, the polarity is reversed.Reverse the leads if this occurs.

37. Switch the dome lamp OFF, then read the meterdisplay and record the reading at left.

Note:Note:Note:Note:Note: With the circuit switch OFF, the ammetershould display less than “0.02 DC”. If thedisplay shows current flow greater than about0.20 amps, there is a parasitic load in thecircuit that will either melt a fuse or eventuallydischarge the battery. If this is the case, furtherdiagnosis is necessary.

As previously noted, some computer-controlled circuits and certain accessories(e.g. clock, radio, power seats, ECM keepalive memory, Smart Entrance control, etc.)may continuously draw a slight amount ofcurrent. Even these circuits will eventuallydischarge a battery if the vehicle is not run fora few weeks.

RECORDANSWER

15Module 18

Module 18

Autorange versus Manual Range Mode

When switched ON, the meter automatically defaultsto “autorange” display. In this mode, the meterautomatically sets to the most accurate scale.

For example, when measuring voltage, the displayautomatically displays any voltage between0-1000 volts.

Pushing the button on the rotary switch changes themeter to manual mode.

Note:Note:Note:Note:Note: The manual range mode allows you to select ascale to obtain the most accuratemeasurement.

Manual ranging is available in V, and A modes.

38. Set the meter to read resistance, then connectthe red and black meter leads to a spark plugcable. Record the resistance at left.

39. Press the button once to go into the manualrange mode. The meter displays the manualrange symbol shown at left.

Note:Note:Note:Note:Note: The meter responds with a “beep” each timethe button is pressed.

40. Press the button again, then record theresistance at left.

RECORDANSWER __________

Manual range symbol


Note movement of decimal point eachtime you push the button

16 Module 18

ECTC0016C

41. Push the button on the rotary switch again, thenrecord the resistance.

42. Push the button a third time, then record theresistance.

43. Push the button a fourth time, then record theresistance.

Note:Note:Note:Note:Note: Each of the above measurements areequivalent (the same). The manual range modeallows you to select a scale to obtain the mostaccurate measurement. For example, theseresistance readings are the same:

10 = .01k = .00001M

44. To return to the default “autorange” display,press the button for 1 second or rotate theswitch to another position.

45. Switch the meter OFF.

46. You have just completed this worksheet. Youshould now be able to identify the differentmeter features, connect the test leads, andperform voltage, resistance, amperage andcontinuity tests. If you have any doubt aboutyour skills in completing this worksheet pleasereturn to step #1 and review your work. Onceyou are confident of your skills, have yourinstructor verify your work.






1Module 19

Module 19

Objective:Objective:Objective:Objective:Objective: Given a digital multimeter, servicemanual and an on-vehicle tank gaugeunit, test the operation of the fuel tankgauge unit and evaluate the testresults.

Relevance:Relevance:Relevance:Relevance:Relevance: Testing the fuel gauge unit and tankunit requires an understanding ofcircuit operation and the ability tolocate circuit specifications. With thatknowledge in mind, circuit testing andevaluation can help you isolate the rootcause of related problems.

Resources:Resources:Resources:Resources:Resources: • Fuel Tank Gauge Unit (on-vehicle)• Fuel Tank Gauge Unit (on bench)• Digital Multimeter• Electronic Service Manual (ESM)

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Use an ohmmeter to measure andrecord the resistance of a tank gaugeunit.

With gauge unit removed from thetank, but connected to the vehiclecircuit, test the operation of the gaugeand low fuel warning light.

Determine corrective action.

FUEL GAUGE TFUEL GAUGE TFUEL GAUGE TFUEL GAUGE TFUEL GAUGE TANK UNIT TESTINGANK UNIT TESTINGANK UNIT TESTINGANK UNIT TESTINGANK UNIT TESTING

2 Module 19

ECTC0016C

1. Using the ELELELELEL section of the service manual as areference, which fuse protects the combinationmeter and what is the amperage rating?

___________________________________

2. Which combination meter terminal(s) is (are)connected through this fuse?

___________________________________

___________________________________

3. The ignition switch supplies voltage to thecombination meter through the terminalidentified in step 2.

List the gauges connected to this fuse:

___________________________________

___________________________________

___________________________________

NoteNoteNoteNoteNote: Identifying a common voltage source can helpisolate malfunctions.

4. What color is the wire that connects the fuelgauge to the fuel tank gauge unit?

___________________________________

5. Do the fuel tank gauge unit and the tachometeruse a common ground connection?


NoteNoteNoteNoteNote: Identifying a common ground can help isolatemalfunctions.

3Module 19

Module 19

6. Referring to the level sensor and chart at left,what should the resistance measure through thefuel tank gauge unit when the float is at the 1/2full position?

____________________________________

NoteNoteNoteNoteNote: The resistance between the fuel gauge andground changes in relation to the floatposition. This specification is different forsome models. Always refer to the appropriateservice manual for specifications.

7. Using a fuel gauge unit (on the bench) and anohmmeter, check the resistance of the gaugeunit.

a. What is the resistance when the tankfloat is held in the “Full” position?

________________________ Ohms

b. Is this reading within specification?


8. What is the resistance with the float in“Position #2”?

______________________________Ohms

4 Module 19

ECTC0016C

9. Is this reading within service manualspecifications?


10. If the resistance in position #2 is 60 ohms, howwould this affect the fuel gauge reading?

__________________________________

Ask your instructor to assign you a test vehicle.

Using the service manual as a reference, gain accessto the fuel gauge tank unit, then perform the testprocedures and answer the following questions.

11. Unplug the fuel gauge unit harness connector,then switch the ignition ON.

What does the fuel gauge read?

____________________________________

12. Connect the gauge unit harness connector tothe bench fuel gauge unit.

13. When you move the float, how long does it takefor the fuel gauge to move?

___________________________________

14. Does the fuel gauge respond as you wouldexpect when you move the float UP andDOWN?


15. Switch the ignition OFF, then locate theWarning Lamp Wiring Diagram in the servicemanual. Perform the following tests on the lowfuel warning lamp circuit.

5Module 19

Module 19

16. Which terminal at the level sensor unit connectorconnects to the ”low fuel” warning lamp?

___________________________________

___________________________________

NoteNoteNoteNoteNote: The warning lamp wiring diagram identifies thelocation and color of this wire.

17. Unplug the bench fuel gauge unit from theharness connector. Connect a fused jumperwire from the low fuel warning lamp terminal to achassis ground.

18. Switch the ignition ON. Does the low fuelwarning lamp glow?


NoteNoteNoteNoteNote: The fuel warning lamp sensor or switchprovides a ground for the warning lamp whenthe fuel level is low. The low fuel warning lamptakes a short time for the bulb to light whenthe ignition is first switched ON.

There are two types of low fuel warningcircuits depending on vehicle application. TheFuel Warning Lamp test varies with the type ofsystem being tested.

6 Module 19

ECTC0016C

19. What type of low fuel warning circuit are youtesting?

___________________________________

20. Reconnect the bench fuel tank gauge unit to thevehicle harness connector, then perform the lowfuel lamp tests as described on page 107 in thetext section.

21. Switch the ignition OFF, then disconnect theharness connector from the bench fuel tankgauge unit.

22. Reconnect the harness onto the installed fueltank gauge unit.

23. A customer is concerned with a warning lampthat does not light when the fuel level is low.After verifying the complaint, what diagnosticstep should you perform to help identify thecause of the malfunction?

___________________________________

___________________________________

___________________________________

You have just completed this worksheet. You shouldnow be able to test the operation of the fuel tankgauge unit and evaluate the test results. If you haveany doubt about your skills in completing thisworksheet please return to step 1 and review yourwork. Once you are confident of your skills, have yourinstructor verify your work.



1Module 20

Module 20Objective:Objective:Objective:Objective:Objective: Given an ASIST/ESM workstation,

identify and interpret the symbols usedin electrical wiring diagrams.

Relevance:Relevance:Relevance:Relevance:Relevance: In order to be efficient at diagnosingelectrical malfunctions, you must beable to read and interpret electricaldiagrams.

The format used in recent servicemanuals makes it easy to identifycomponents and trace the current pathfrom the battery, through the circuitand to ground. This module providesan opportunity for you to practicelocating, identifying and interpretingelectrical diagrams.

Resources:Resources:Resources:Resources:Resources: • ASIST• ESM (Electronic Service Manual)

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Identify and describe various electricalsymbols used in service manual wiringdiagrams.

SERVICE MANUAL ELECTRICAL SYMBOLS

2 Module 20

ECTC0016C


J J J J J

BBBBB

HHHHH

FFFFF

AAAAA

CCCCC

FFFFFGGGGG

KKKKK

I I I I I

DDDDD

EEEEE

FFFFF

3Module 20

Module 20

1. Using the electrical wiring diagram in Figure 1as a reference, enter a description of thecomponents identified by the lettered callouts inthe chart at left.

A.

B.

C.

D.

E.

F.

G.

H.

I.

J.

K.

2. In the diagram at left, why is the line betweenterminals 14 and 1 wider than the line betweenterminals 16 and 2? (Choose one)

a. The wider line illustrates a greatercurrent carrying capacity of that circuit.

b. The wider line represents a shield fromelectromagnet interference (EMI) forthe other circuit.

c. The wider line represents a fusiblematerial to protect both the vehiclespeed sensor and the ECM fromvoltage spikes.

d. The wider line represents a “detectableline for diagnostic trouble code” (DTC)On-board Diagnostics.

4 Module 20

ECTC0016C

CCCCC

AAAAA

BBBBB


5Module 20

Module 20

3. Refer to the circuit in Figure 2 and the GI sectionof the service manual to complete steps 4–8.

4. What are the harness connector numbers in thecircuit between the electric speedometer andthe ECM?

_________________

_________________

5. Identify the electrical symbols that correspondto the letters below:

A._______________________________

B._______________________________

C._______________________________

6. What do the dashed lines between terminals 7and 6, C4 and B2, and 5 and 1 represent?

_________________________________

_________________________________

7. What amperage fuse protects the combinationmeter?

_________________________________

8. What is the wire color for the circuit thatsupplies voltage to the combination meter?

__________________________________

6 Module 20

ECTC0016C

9. Identify and record the terminal test points foreach of the combination meter componentslisted in the chart at left.

10. How many combination meter/gauge terminalsare housed inside connector M69?

_________________________________

11. What does the dashed outline around the twoconnectors (M65 and M66) at the bottom ofFigure 2 represent?

_________________________________

_________________________________

12. Identify the Wiring Diagram Codes (Cell Codes)and the section where they can be found in theservice manual in the chart at left.

NoteNoteNoteNoteNote: For additional information on electricaldiagrams and Cell Codes, refer to the GI andEL sections of the service manual. In addition,review the video, Service Manual Usage -Service Manual Usage -Service Manual Usage -Service Manual Usage -Service Manual Usage -Electrical.Electrical.Electrical.Electrical.Electrical.

You have just completed this worksheet. You shouldnow be able to identify and interpret the symbols usedin electrical wiring diagrams. If you have any doubtabout your skills in completing this worksheet pleasereturn to step 1 and review your work. Once you areconfident of your skills, have your instructor verify yourwork.



ComponentComponentComponentComponentComponent TTTTTerminal Terminal Terminal Terminal Terminal Test Pest Pest Pest Pest Pointsointsointsointsoints

GroundGroundGroundGroundGroundSourceSourceSourceSourceSourceVVVVVoltageoltageoltageoltageoltage

SignalSignalSignalSignalSignal

Speedometer

Tachometer

Fuel Gauge

Water Temp.Gauge

CodeCodeCodeCodeCode DescriptionDescriptionDescriptionDescriptionDescription SMSMSMSMSM Section Section Section Section Section

TPS

ATDIAG

DEF

KS

DTRL

1Module 21

Module 21

ObjectiveObjectiveObjectiveObjectiveObjective: Given a vehicle, digital multimeterand Model 620 Tester, test thebattery, starter and charging system.

RelevanceRelevanceRelevanceRelevanceRelevance: The importance of visual inspectionsmust not be overlooked whendiagnosing malfunctions associatedwith the battery, starter and chargingsystem. It is also important that youdetermine that parasitic loads are notdraining the battery. If, after completingthese steps, the root cause has notbeen pinpointed, use the J-44373,Model 620 Tester to check eachsystem. It is a required tool. It displaystest result codes which must berecorded on all warranty-related repairorders.

Resources:Resources:Resources:Resources:Resources: • A vehicle• CONSULT II• J-44373 Model 620 Tester• Digital multimeter

Skill Check:Skill Check:Skill Check:Skill Check:Skill Check: Confirm visual inspection, measure andrecord parasitic load, then set dateand time on J-44373 and record alltest results.

TESTING BATTERIES, STARTERS &CHARGING SYSTEMS

2 Module 21

ECTC0016C

1. Go to the assigned vehicle.

2. Visually inspect battery cables and batteryterminals to confirm connections are tight and ingood condition. If there is corrosion orconnections are loose, correct these conditionsbefore continuing.

Record unsatisfactory conditions here:

_________________________________

_________________________________

3. Measure and record the available batteryvoltage.

________ Volts _______ % Charge

NoteNoteNoteNoteNote: By measuring available battery voltage youestablish the battery’s state of charge andconfirm a customer concern of hard starting orno-start condition.

4. If the available voltage is low, check for parasiticload to determine if something is draining thebattery when all circuits should be OFF.

Conduct a Parasitic Load test as follows:Conduct a Parasitic Load test as follows:Conduct a Parasitic Load test as follows:Conduct a Parasitic Load test as follows:Conduct a Parasitic Load test as follows:

5. Switch ignition OFF and remove the key.

6. Close all doors and the rear hatch.

7. With the hood open, disconnect the anti-theftswitch (if equipped).

8. Switch the multimeter to measure DC Amps.

9. Connect the red lead to the negative batterycable connector.

Voltage % of Charge

12.60 V 100%

12.45 V 75%

12.30 V 50%

12.15 V 25%

Battery State of ChargeBattery State of ChargeBattery State of ChargeBattery State of ChargeBattery State of Charge

3Module 21

Module 21

10. Loosen, but do not remove the negative batterycable.

11. Connect the black lead to the negative batterypost below the cable connector.

12. Remove the negative battery cable while themeter leads are still attached to the battery postand the cable.

Note:Note:Note:Note:Note: This ensures the customer’s preset radio andauto air conditioning controls are not eraseddue to a temporary loss of voltage.

13. Wait 2 minutes, then record the meter reading inthe spaces below. Record both the amps andmilli-amps readings:

________ A ___________mA

Note:Note:Note:Note:Note: General Specification GuidelinesGeneral Specification GuidelinesGeneral Specification GuidelinesGeneral Specification GuidelinesGeneral Specification Guidelines(after battery disconnected 2 minutes):

.00 – .02 amps (0–20 mA) Good

.02 – .05 amps (20–50 mA) Questionable

.05 amps (50 mA and above) No Good(Something isdraining thebattery)

14. Is your reading within the Good (normal)operating range?


WWWWWARNINGARNINGARNINGARNINGARNINGDO NODO NODO NODO NODO NOT AT AT AT AT ATTEMPT THIS TEST ON ATTEMPT THIS TEST ON ATTEMPT THIS TEST ON ATTEMPT THIS TEST ON ATTEMPT THIS TEST ON ALEAD-ACID BALEAD-ACID BALEAD-ACID BALEAD-ACID BALEAD-ACID BATTERTTERTTERTTERTTERY THAY THAY THAY THAY THAT HAST HAST HAST HAST HASRECENTLRECENTLRECENTLRECENTLRECENTLY BEEN RECHARGED.Y BEEN RECHARGED.Y BEEN RECHARGED.Y BEEN RECHARGED.Y BEEN RECHARGED.EXPLEXPLEXPLEXPLEXPLOSIVE GASES MIGHT BE PRESENTOSIVE GASES MIGHT BE PRESENTOSIVE GASES MIGHT BE PRESENTOSIVE GASES MIGHT BE PRESENTOSIVE GASES MIGHT BE PRESENT.....

CAUTIONCAUTIONCAUTIONCAUTIONCAUTIONDo not crank the engine or operateDo not crank the engine or operateDo not crank the engine or operateDo not crank the engine or operateDo not crank the engine or operateaccessories that draw more than 10Aaccessories that draw more than 10Aaccessories that draw more than 10Aaccessories that draw more than 10Aaccessories that draw more than 10A. Y. Y. Y. Y. Youououououcould melt the fuse in the metercould melt the fuse in the metercould melt the fuse in the metercould melt the fuse in the metercould melt the fuse in the meter

Note:Note:Note:Note:Note:Many computers draw 10 mA or morecontinuously.

Measuring Parasitic Current DrawMeasuring Parasitic Current DrawMeasuring Parasitic Current DrawMeasuring Parasitic Current DrawMeasuring Parasitic Current Draw

Red

Black

COM

V

300 m

–+

10A

Remove fuseto identifycircuit

4 Module 21

ECTC0016C

15. If the amperage draw is excessive (above 50mA), what steps should you take to isolate theparasitic load and repair the malfunction?

___________________________________

___________________________________

Note:Note:Note:Note:Note: By performing each of the above steps, younow have a thorough understanding of thebattery’s general condition. By confirmingconnections and then testing for parasiticloads you know whether additional testing isnecessary.

Remember that poor connections andaccessories left ON can affect operation of allelectrical systems because of excessivebattery drain.

16. Confirm that the engine is at normal operatingtemperature.

NoteNoteNoteNoteNote: When performing this procedure on acustomer’s vehicle, the engine temperaturemust be recorded on the repair order. UseCONSULT-II to find the actual enginetemperature.

17. Confirm the engine oil level is correct and makesure that the recommended weight of engine oilis being used.

Is the oil level full?


Is the oil viscosity correct?


5Module 21

Module 21

Note:Note:Note:Note:Note: Engine operating temperature and correctengine oil and oil level are all checked as ameans of providing support data for thestarter test. When performing the battery teston a customer’s car, record the engine coolanttemperature on the repair order.

18. Turn the ignition OFF.

19. Visually inspect the battery, terminals and cableends. Clean as necessary. If the battery case iscracked or the terminals are damaged, thebattery must be replaced before performing thetests. Note the battery condition below:

_____________________________________

20. Before performing any tests, be certain to setthe date and time on the tester. To do this, withthe tester disconnected from the battery, pressMENUMENUMENUMENUMENU.

21. Use the to scroll through the list until you findthe “SET DATE & TIME” selection, then pressENTERENTERENTERENTERENTER to confirm the date and time. If the dateor the time are not correct, press the tochange the setting.

22. When the setting is correct, press ENTERENTERENTERENTERENTER toadvance to the next “cell”. When each of thecells has been changed so that the date andtime are now correct, press ENTERENTERENTERENTERENTER to end thismode.

Note:Note:Note:Note:Note: Failure to set the correct time and date willresult in improper claims coding andreimbursement for the repair will be denied. Becertain the date is correct before performingthe test.

6 Module 21

ECTC0016C

23. Using the Model 620 tester, attach the twoalligator clip leads to the battery cables. Attachthe red lead to the positive battery post (+), andthe black lead to the negative battery post (–),also known as the ground cable ( ). Each ofthe test leads must be securely connected orthe tester will not operate.

24. With the tester leads attached to the batterycables, the tester automatically comes on. Thedisplay at left appears. If it did not startautomatically, check both cable connectionsbefore proceeding.

25. Make sure all accessory loads are turned off andthat the ignition switch is OFF before performingthe battery test.

26. Locate the IN-VEHICLE test. It may benecessary to scroll down the list to find thisparticular test. To do so, press until that testappears, then press ENTERENTERENTERENTERENTER to select it. Thisshould bring up the screen at left.

27. To perform battery tests, the tester must beprogrammed to know the battery’s ratingsystem. In order to test batteries on Nissanvehicles, choose Cold Cranking Amps (CCA)Cold Cranking Amps (CCA)Cold Cranking Amps (CCA)Cold Cranking Amps (CCA)Cold Cranking Amps (CCA)or Japanese Industrial Standard (JIS)Japanese Industrial Standard (JIS)Japanese Industrial Standard (JIS)Japanese Industrial Standard (JIS)Japanese Industrial Standard (JIS) for therating type. Most new cars will come withbatteries that have the JIS rating. This rating islocated on the top of the battery case. Anexample JIS rating is 80D26L.

28. For this exercise, locate either the JIS or CCArating. To do this, press on the keypad toscroll down until the desired choice is showing,then Press ENTER ENTER ENTER ENTER ENTER to select it. The screen atleft appears.

CHOOSE TEST ??OUT-OF-VEHICLE ?

SELECT INPUT ??TEST USING: CCA?

SET JIS# ? ? 80D26 ?

7Module 21

Module 21

29. Press to scroll down the list until you find thecorrect battery rating for the battery you aretesting, then press ENTERENTERENTERENTERENTER to select thatchoice. After choosing the battery rating, thetester automatically performs the battery test.While the test is being conducted, the screen atleft appears.

Note:Note:Note:Note:Note: The tester may give an indication that thebattery has a surface charge which must beremoved prior to testing the battery. If thishappens, follow the instructions on the tester,then continue with the test.

30. When the test is complete, the test result isdisplayed. The result will resemble the resultshown at left. Notice that the tester displaytoggles between the “TEST RESULTS” and“PRESS ENTER FOR BATTERY CODE”.

NoteNoteNoteNoteNote: When performing this procedure on a vehicle,it is essential to record all 12 characters of thecode on the repair order. Failure to do so willresult in the claim being denied or suspended.

*** TESTING***80D26

12.71V 506CCAGOOD BATTERY

BATTERY CODEBATOR-DRL8N30

8 Module 21

ECTC0016C

31. Press ENTER ENTER ENTER ENTER ENTER to find out the test code, thenrecord both the test results and the test codebelow:

Record test results here.

__________________________________

Record the 12 character test code here.

__________________________________

Note:Note:Note:Note:Note: A screen similar to the one at left shouldappear with the code. Notice once again thatthe screen display toggles. This feature isconsistent with each of the remaining tests, sofurther mention is not necessary.

32. Press ENTERENTERENTERENTERENTER to advance to the starting systemtest. The prompt ”START ENGINE” appears. Atthis time, start the engine. While doing this, thetester will perform a starting system test. Ascreen similar to the one at left should appear atthe end of the test. Record the test resultbelow:

Starting System test result.

________________________________________

33. Press ENTERENTERENTERENTERENTER to advance to the ChargingSystem test. A screen similar to the one at leftappears, showing the charging system outputvoltage.

34. Press ENTER ENTER ENTER ENTER ENTER to continue. Confirm that allelectrical loads are switched OFF beforecontinuing with the next step. The screen at leftappears.

CRANKING VOLTAGENORMAL 10.74V

ALT VOLTS: 14.53VENTER TO CONT...

LOADS OFFREV ENGINE FOR 5 SEC

9Module 21

Module 21

35. Rev the engine to about 1500-2000 RPM for 5seconds. When the tester detects RPM, thescreen at left appears. Release the throttle andlet the engine idle.

*** TESTING ***DIODE/RIPPLE

*** TESTING ***ENGINE @ IDLE

RPM DETECTEDENTER TO CONT...

ENTER TO CONTINUE...AFTER REVVING

ANALYZING DATAPLEASE WAIT

RPM DETECTEDENTER TO CONT...

*** TESTING ***AT IDLE LOADS ON

TURN LOADS ONENTER TO CONT...

36. After releasing the throttle, press ENTERENTERENTERENTERENTER. Atidle, the tester conducts a Diode Ripple test,then prompts you to apply loads.

37. Turn ON the high beam headlamps, the rearwindow defogger, and the blower on high(heat). Do not use cyclical loads such as the airconditioner or windshield wipers as inaccurateresults will occur.

38. Again, rev the engine to about 1500-2000 RPMfor 5 seconds. When the tester detects rpm, thescreen at left appears.

39. Press ENTERENTERENTERENTERENTER to continue. The screen at leftappears while the test is being conducted.

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ECTC0016C

40. At the conclusion of the charging system test,the series of screens at left will toggle, indicatingthe overall condition of the charging system.

PRESS ENTER FORCHARGING CODE

IDLE VOLTS: 14.00VLOAD VOLTS: 14.08V

DIODE RIPPLENORMAL

CHARGING SYSTEMNORMAL

CHARGING CODEALTST-2ST483T

41. Press ENTERENTERENTERENTERENTER to find out the test code, thenrecord both the test results and the test codebelow:

Charging System voltage ____________

Diode Ripple ______________________

42. Record the 12 character test code below:

______________________________________

Note:Note:Note:Note:Note: The 12 character test code that appears atthe end of testing is the same code forstarters and charging systems. This codemust also be recorded on the repair order forboth the Starter test and the Battery test.

11Module 21

Module 21

43. Based on the results of these tests, whatconclusions can you make about the conditionof the battery, starter, and charging system?Look at the following list of options and checkeach one that matches your results:

Battery Condition:

• GOOD BATTERY—Return to service.

• GOOD-RECHARGE—Fully charge battery andreturn to service.

• CHARGE & RETEST—Fully charge the batteryand retest it. Failure to fully charge the batterybefore retesting may cause false readings.

• REPLACE BATTERY—Replace the battery andretest to perform a complete charging systemanalysis. If this result appears, check batterycable connections and perform an out-of-vehicletest on the battery before replacing the battery.If it fails the out-of-vehicle test, it should bereplaced.

• BAD CELL-REPLACE—Replace the battery andretest to perform a complete system analysis.

Note:Note:Note:Note:Note: If charge and retest result appears for thebattery test, charge the battery, then performthe test again. Make certain that you select“After Charge” when you enter the type of testor the battery may again fail the test.

12 Module 21

ECTC0016C

Starter Condition:

• CRANKING VOLTAGE NORMAL—The systemshows normal starter draw.

• CRANKING VOLTAGE LOW—The crankingvoltage is below normal limits, troubleshoot thestarter. Refer to the service manual or bulletinsassociated with this vehicle for additionalinformation relating to the starting system.

• CHARGE BATTERY—The battery state-of-charge was too low to perform a startingsystem test. Charge the battery, then continuewith the starting system test.

• REPLACE BATTERY—The battery must bereplaced before testing the starter. Replace it,then continue with the starting system test.

Charging System Condition:

• CHARGING SYSTEM NORMAL/DIODERIPPLE NORMAL—The system is showingnormal output from the alternator. No incidentdetected.

• NO CHARGING VOLTAGE—The alternator isnot developing any charging voltage to keep thebattery charged.

• LOW CHARGING VOLTAGE—The alternator isnot providing sufficient current for the system’selectrical loads and to keep the battery charged.

• HIGH CHARGING VOLTAGE—The voltageoutput from the alternator exceeds the normallimits of a functioning regulator.

• EXCESS RIPPLE DETECTED—One or morediodes are not functioning or there is statordamage.

13Module 21

Module 21

Attach Printout Here Attach Printout Here Attach Printout Here

You have just completed this worksheet. You shouldnow be able to perform a parasitic load test and testthe battery, starter and charging systems. If you haveany doubt about your skills in completing thisworksheet please return to step 1 and review yourwork. Once you are confident of your skills, have yourinstructor verify your work.



14

NOTES

Module 21

NOTES

STARTING SYSTEM

NOTE: DISABLE IGNITION SYSTEM THEN CRANK VEHICLE.

MAXIMUM ALLOWABLEVOLTAGE DROPS

Wire connections — 0.0 VoltsGround connections — 0.1 Volts

Switch contacts — 0.3 VoltsStarter Solenoids — 0.5 Volts

TROUBLESHOOTING TIPS

TIP #1TIP #1TIP #1TIP #1TIP #1 An open at any point in a series circuit will prevent the entire circuitfrom operating.

TIP #2TIP #2TIP #2TIP #2TIP #2 An open in a parallel circuit prevents only the LOAD in the openpath from operating.

TIP #3TIP #3TIP #3TIP #3TIP #3 If both LOADs in a parallel circuit are not operating, look for theproblem to be BEFORE the circuits split.

TIP #4TIP #4TIP #4TIP #4TIP #4 If an entire circuit is dead, the problem is with a series component,such as a switch or POWER.

TIP #5TIP #5TIP #5TIP #5TIP #5 Fuses and fusible links blow because of increased current flow(reduced resistance) in the circuit between POWER andGROUND.

TIP #6TIP #6TIP #6TIP #6TIP #6 If an unwanted GROUND occurs on the GROUND side of a LOADin a ground switched circuit, the LOAD will stay on all the time.

1

Course TitleCourse Title

ELECTRICAL COMPONENT DIAGNOSIS AND REPAIR

May 2003

Slide 1

Course ScheduleCourse Schedule

• Start/End Time• Breaks• Lunch• Smoking Areas

• Phones• Shop Safety• Emergency Procedures• First Aid

• Fire ExitsSlide 2

Course MapCourse Map

Slide 3

2

Course Map, Cont.Course Map, Cont.

Slide 4

Connector GuidesConnector Guides

Slide 6

Connector Symbols in CircuitsConnector Symbols in Circuits

Slide 5

3

Connector SymbolConnector Symbol

X

Connector Symbol

No Terminal

Slide 7

Connector Direction MarkConnector Direction Mark

Slide 8

Connector SymbolsConnector Symbols

Slide 9

4

Harness Layout DiagramHarness Layout Diagram

Slide 10

Harness LayoutHarness Layout

Slide 11

Foldout Diagrams Foldout Diagrams

Slide 12

5

Power Supply RoutingPower Supply Routing

Slide 13

Ground DistributionGround Distribution

Slide 14

ASIST/ESM MenuASIST/ESM Menu

Slide 15

6

Analog MeterAnalog Meter

Slide 16

Digital Digital MultimeterMultimeter

Slide 17

DMM Scale: OhmsDMM Scale: Ohms

Slide 18

7

J44373 Battery, Starter, Charging TesterJ44373 Battery, Starter, Charging Tester

Slide 19

Circuit RequirementsCircuit Requirements

Slide 20

VoltageVoltage

Slide 21

8

CurrentCurrent

Slide 22

Circuit ResistanceCircuit Resistance

Slide 23

Circuit ConductorsCircuit Conductors

Slide 24

9

Series CircuitSeries Circuit

Slide 25

Parallel CircuitParallel Circuit

Slide 26

SeriesSeries--Parallel CircuitParallel Circuit

Slide 27

10

Excessive ResistanceExcessive Resistance

Slide 28

Crossover vs. Short CircuitCrossover vs. Short Circuit

Slide 29

Circuit ProtectionCircuit Protection

Slide 30

11

NO, NC and Combination SwitchesNO, NC and Combination Switches

Slide 31

Relay ConstructionRelay Construction

Slide 33

SwitchSwitch--Controlled CircuitsControlled Circuits

Slide 32

12

1M Relay1M Relay

Slide 34

Simulator Overlay #3Simulator Overlay #3

Slide 36

1M Relay in Circuit1M Relay in Circuit

Slide 35

13

1T Relay1T Relay

Slide 37


Slide 39

1T Relay in Circuit1T Relay in Circuit

Slide 38

14

2M Relay2M Relay

Slide 40


Slide 42

2M Relay in Circuit2M Relay in Circuit

Slide 41

15

1M1M--1B Relay1B Relay

Slide 43


Slide 45

1M1M--1B Relay in Circuit1B Relay in Circuit

Slide 44

16

Parts of a RelayParts of a Relay

Slide 46

Nissan Relay Types: Chart 1Nissan Relay Types: Chart 1

Slide 47

Nissan Relay Types: Chart 2Nissan Relay Types: Chart 2

Slide 48

17

Measuring Available VoltageMeasuring Available Voltage

Slide 49

Measuring Voltage DropMeasuring Voltage Drop

Slide 50

Measuring CurrentMeasuring Current

Slide 51

18

Digital & Analog CyclesDigital & Analog Cycles

Slide 54

Starting SystemStarting System

Slide 52

Charging SystemCharging System

Slide 53

19

Cycle Frequency VSSCycle Frequency VSS

Slide 55

Duty Cycle %Duty Cycle %

Slide 56

Repair Order (blank)Repair Order (blank)

Slide 57

1

NOTES

2

NOTES

3

NOTES

4

NOTES

5

NOTES

6

NOTES

7

NOTES

8

NOTES

9

NOTES

10

NOTES

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Nissan Electrical Components Diagnosis and Repair (1)

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