ISUZU TROOPER 1998 Service Repair Manual

8C–8ENTERTAINMENT
Front Speaker
Removal
1. Disconnect the battery ground cable.
2. Pull the grille(1) to release the locks and then remove
it.
3. Remove four screws and disconnect the
connector(3) to remove the speaker(2).
890RW013
Installation
To install, follow the removal steps in the reverse order.

ENTERTAINMENT8C–9
Rear Speaker
Removal
1. Disconnect the battery ground cable.
2. Pull the grille(1) to release the locks and then remove
it.
3. Remove four screws and disconnect the
connector(3) to remove the speaker(2).
890RW015
Installation
To install, follow the removal steps in the reverse order.

8C–10ENTERTAINMENT
MEMO

WIRING SYSTEM 8DÐ1
BODY AND ACCESSORIES
WIRING SYSTEM
CONTENTS
Service Precautions . . . . . . . . . . . . . . . . . . . 8DÐ3
General Description . . . . . . . . . . . . . . . . . . . 8DÐ4Notes for Working on Electrical Items . . 8DÐ4
Symbols and Abbreviations . . . . . . . . . . . 8DÐ10
Parts for Electrical Circuit . . . . . . . . . . . . . 8DÐ12
Reading the Circuit Diagram . . . . . . . . . . 8DÐ21
Main Data and Specifications . . . . . . . . . . . 8DÐ24 Fuse, Fusible Link and Circuit Breaker Location . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ24
Relay Location . . . . . . . . . . . . . . . . . . . . . . 8DÐ27
Diode Location . . . . . . . . . . . . . . . . . . . . . . 8DÐ30
Grounding Point . . . . . . . . . . . . . . . . . . . . . 8DÐ33
Cable Harness Routing . . . . . . . . . . . . . . . 8DÐ45
Fuse Block Circuit . . . . . . . . . . . . . . . . . . . . . 8DÐ53 Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ54
Start and Charging . . . . . . . . . . . . . . . . . . . . 8DÐ67 General Description . . . . . . . . . . . . . . . . . . 8DÐ67
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ68
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ70
Powertrain Control Module (PCM) . . . . . . . 8DÐ80 General Description . . . . . . . . . . . . . . . . . . 8DÐ80
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ81
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ93
QOSIII (4JG2) . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ111 General Description . . . . . . . . . . . . . . . . . . 8DÐ111
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ112
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ114
QOS and EGR System (4JG2) . . . . . . . . . . . 8DÐ118 General Description . . . . . . . . . . . . . . . . . . 8DÐ118
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ119
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ122
Headlight and Fog Light . . . . . . . . . . . . . . . . 8DÐ127 General Description . . . . . . . . . . . . . . . . . . 8DÐ127
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ128
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ130
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ134
Rear Foglight . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ150 Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ151
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ152
Headlight Leveling . . . . . . . . . . . . . . . . . . . . 8DÐ153 General Description . . . . . . . . . . . . . . . . . . 8DÐ153
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ154
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ155
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ156
Clearance Light, Taillight and License Plate Light . . . . . . . . . . . . . . . . . . . . 8DÐ159 General Description . . . . . . . . . . . . . . . . . . 8DÐ159
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ160
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ163
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ168
Interior Illumination Light . . . . . . . . . . . . . . 8DÐ180 General Description . . . . . . . . . . . . . . . . . . 8DÐ180
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ181
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ185
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ192
Turn Signal Light and Hazard Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ193
General Description . . . . . . . . . . . . . . . . . . 8DÐ193
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ194
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ197
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ202
Stoplight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ208 General Description . . . . . . . . . . . . . . . . . . 8DÐ208
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ209
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ212
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ216
Backup Light. . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ220 General Description . . . . . . . . . . . . . . . . . . 8DÐ220
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ221
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ223
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ227
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ230 General Description . . . . . . . . . . . . . . . . . . 8DÐ230
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ231
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ232
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ235
Dome Light, Luggage Room Light, Courtesy Light and Map Light . . . . . . . . . . 8DÐ237
General Description . . . . . . . . . . . . . . . . . . 8DÐ237
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ238
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ240
Power Door Lock . . . . . . . . . . . . . . . . . . . . . . 8DÐ244 General Description . . . . . . . . . . . . . . . . . . 8DÐ244
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ245
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ250
Diagnosi s. . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ2 56
Power Window . . . . . . . . . . . . . . . . . . . . . . . 8DÐ261 General Description . . . . . . . . . . . . . . . . . . 8DÐ261
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ262
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ263
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ266
Cruise Control . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ272

8DÐ2 WIRING SYSTEM
General Description . . . . . . . . . . . . . . . . . . 8DÐ272
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ273
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ275
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ279
AntiÐLock Brake System (ABS) . . . . . . . . . . 8DÐ284
General Description . . . . . . . . . . . . . . . . . . 8DÐ284
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ285
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ291
A/T Shift Lock . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ298
General Description . . . . . . . . . . . . . . . . . . 8DÐ298
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ299
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ300
Windshield Wiper/Washer . . . . . . . . . . . . . . 8DÐ303
General Description . . . . . . . . . . . . . . . . . . 8DÐ303
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ304
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ305
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ308
Rear Wiper/Washer . . . . . . . . . . . . . . . . . . . . 8DÐ316
General Description . . . . . . . . . . . . . . . . . . 8DÐ316
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ317
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ319
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ323
Headlight Wiper/Washer . . . . . . . . . . . . . . . 8DÐ329
General Description . . . . . . . . . . . . . . . . . . 8DÐ329
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ330
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ332
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ336
Rear Defogger . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ342
General Description . . . . . . . . . . . . . . . . . . 8DÐ342
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ343
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ344
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ347
Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ350
General Description . . . . . . . . . . . . . . . . . . 8DÐ350
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ351
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ355
Cigarette Lighter and Digital Clock . . . . . . . 8DÐ359
General Description . . . . . . . . . . . . . . . . . . 8DÐ359
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ360
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ361
Power Door Mirror . . . . . . . . . . . . . . . . . . . . 8DÐ364
General Description . . . . . . . . . . . . . . . . . . 8DÐ364
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ365
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ368
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ373
AntiÐTheft System with Keyless Entry . . . . 8DÐ380
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ381
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ392
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ399Meter and Warning/Indicator Light . . . . . . 8DÐ410
General Description . . . . . . . . . . . . . . . . . . 8DÐ410
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ411
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ429
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ445
A/T Shift Indicator . . . . . . . . . . . . . . . . . . . . . 8DÐ464
General Description . . . . . . . . . . . . . . . . . . 8DÐ464
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ465
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ467
Heater and Air Conditioning . . . . . . . . . . . . 8DÐ471
General Description . . . . . . . . . . . . . . . . . . 8DÐ471
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ472
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ474
Sun Roof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ484
General Description . . . . . . . . . . . . . . . . . . 8DÐ484
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ485
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ486
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ489
Seat Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ493
General Description . . . . . . . . . . . . . . . . . . 8DÐ493
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ494
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ495
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ498
Power Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ500
General Description . . . . . . . . . . . . . . . . . . 8DÐ500
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ501
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ503
Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ507
Shift on the Fly System . . . . . . . . . . . . . . . . 8DÐ513
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ514
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ516
Torque on Demand (TOD) . . . . . . . . . . . . . . 8DÐ538
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ539
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ542
Supplemental Restraint System (SRS)Ð
AIR BAG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ543
General Description . . . . . . . . . . . . . . . . . . 8DÐ543
Circuit Diagram. . . . . . . . . . . . . . . . . . . . . . 8DÐ544
Parts Location . . . . . . . . . . . . . . . . . . . . . . . 8DÐ548
Connector List . . . . . . . . . . . . . . . . . . . . . . . . 8DÐ550

WIRING SYSTEM 8DÐ3
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING, REFER TO
THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN POSSIBLE
AIR BAG DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fasteners joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fasteners.
When you install fasteners, use the correct
tightening sequence and specifications. Following
these instructions can help you avoid damage to
parts and systems.

8DÐ4 WIRING SYSTEM
The chassis electrical system is a 12Ðvolt system with a
negative ground polarity.
Wire size are appropriate to respective circuits, and
classified by color. (The classification of harnesses by
color is shown on the circuit diagram for ease of harness
identification.)
The wire size is determined by load capacity and the
length of wire required.
The vehicle harnesses are: body harness, chassis
harness, engine room harness, instrument harness,
transmission harness, engine ECGI harness, dome light
harness, door harness, rear body harness, tailgate
harness, SRS harness and battery cables.
The harnesses are protected either by tape or corrugated
tube, depending on harness location.
The circuit for each system consists of the power source,
wire, fuse, relay, switch, load parts and ground, all of
which are shown on the circuit diagram.
In this section, each electrical device is classified by
system.
For major parts shown on the circuit based on the circuit
diagram for each system, a summary, diagnosis of
troubles and inspection procedures are detailed.
Notes for Working on Electrical
Items
Disconnecting the Battery Cable
1. All switches should be in the ÒOFFÓ position.
2. Disconnect the battery ground cable (2).
3. Disconnect the battery positive cable (1).
CAUTION: It is important that the battery ground
cable be disconnected first. Disconnecting the
battery positive cable first can result in a short circuit.
Connecting the Battery Cable
Follow the disconnecting procedure in the reverse order.CAUTION: Clean the battery terminal and apply a
light coat of grease to prevent terminal corrosion.
Disconnecting the Connector
Some connectors have a tang lock to hold the connectors
together during vehicle operation.
Some tang locks are released by pulling them towards
you (1).
Other tang locks are released by pressing them forward
(2).
Determine which type of tang lock is on the connector
being handled.
Firmly grasp both sides (male and female) of the
connector (3).
Release the tang lock and carefully pull the two halves of
the connector apart.
Never pull on the wires to separate the connectors (4).
2
1
General Description
1
2
3
4

WIRING SYSTEM 8DÐ5
When removing the connector for relay (MR5B type) (5),
unfasten the tang lock of the connector by using a
screwdriver, then pull the relay out as shown in the figure.
Connecting the Connector
Firmly grasp both sides (male and female) of the
connectors. Be sure that both sides of the connectors are
aligned with each other.
Firmly but carefully push the two sides of the connectors
together until a distinct click is heard (2).
Do not connect them by force if they can not be connected
smoothly (1).
Connector Inspection
Use a circuit tester to check the connector for continuity.
Insert the test probes (1) from the connector wire side.
Never insert the circuit tester test probes (2) into the
connector open end to test the continuity.
Broken or open connector terminals will result.
5
1
2
1
2

8DÐ6 WIRING SYSTEM
Waterproof Connector Inspection
It is not possible to insert the test probes (2) into the
connector wire side of a waterproof connector.
Use one side of a connector (1) with its wires cut to make
the test. Connect the test connector to the connector to
be tested (3). Connect the test probes to the cut wires to
check the connector continuity.
Connector Pin Removal Ð Connector
Housing Tang Lock Type
1. Insert a slender shaft (1) into the connector housing
open end (5).
2. Push the tang lock (2) up (in the direction of the arrow
in the illustration).
Pull the wire (3) with pin (4) free from the wire side of
the connector.
Connector Pin Removal Ð Pin Tang Lock
Type
1. Insert a slender shaft (1) into the connector housing
open end (5).
2. Push the tang lock (2) flat (toward the wire (3) side of
the connector.
Pull the wire with pin (4) free from the wire side of the
connector.
Connector Pin Insertion
1. Check that the tang lock (1) is fully up.
2. Insert the pin (3) from the connector wire (2) side.
Push the pin in until the tang lock closes firmly.
3. Gently pull on the wires to make sure that the
connector pin is firmly set in place.
1
3
21
2
3
5
4
1
2
3
4 51
2
3

WIRING SYSTEM 8DÐ7
Parts Handling
Be careful when handling electrical parts. They should not
be dropped or thrown, because short circuit or other
damage may result.
Cable Harness
1. When installing the parts, be careful not to pinch or
wedge the wiring harness.
2. All electrical connections must be kept clean and tight.3. Use a grommet or guard tube (1) to protect the wiring
harness from contacting a sharp edge or surface (2).
4. Position the wiring harness with enough clearance
from the other parts and guard the wiring harness with
a vinyl tube (2) and clips (1) to avoid direct contact.
12
2
1