1998 ISUZU TROOPER fuse chart

8D – 498 WIRING SYSTEM
Diagnosis
Quick Chart for Check Points
Trouble modeCheck point
Seat heater on both sides does not heat up
Seat heater on the driver (or passenger)
side does not heat up
Heat (or keep) position does not heat up
1.
2.
3.
Fuse C-2
(15A)Seat heater SW
Driver sidePassenger
sideHeat unit
Driver sidePassenger
side
Cable
harness
1. Seat Heater on Both Sides Does Not Heat Up
YES
REPLACE THE FUSE
NO
•IS FUSE C-2 (15A) NORMAL?
IS B-26 GROUNDED SECURELY?
YES
GROUND IT SECURELY
NO
•
REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN C-2 (15A) AND 2 B-29
(2 B-31 )

SUPPLEMENTAL RESTRAINT SYSTEM 9J±30
Service Precautions for SRS
Component Service
CAUTION: When fasteners are removed, always
reinstall them at the same location from which they
were removed. If a fastener needs to be replaced, use
the correct part number fastener for that application.
If the correct part number fastener is not available, a
fastener of equal size and strength (or stronger) may
be used. fasteners that are not reused, and those
requiring thread locking compound will be called
out. The correct torque value must be used when
installing fasteners that require it. If the above
conditions are not followed, parts or system damage
could result.
WARNING: WHEN PERFORMING SERVICE ON OR
AROUND SRS COMPONENTS OR SRS WIRING,
FOLLOW THE PROCEDURES LISTED BELOW TO
TEMPORARILY DISABLE THE SRS. FAILURE TO
FOLLOW PROCEDURES COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY OR OTHERWISE UNNEEDED SRS REPAIRS.
The SDM in Driver±Passenger SRS can maintain
sufficient voltage to cause a deployment for up to 15
seconds after the ignition switch is turned ªOFF,º the
battery is disconnected, or the fuse powering the SDM is
removed.
Many of the service procedures require removal of the
ªC±21º fuse, and disconnection of the air bag assembly
from the deployment loop to avoid an accidental
deployment. If the air bag assembly is disconnected from
the deployment loop as noted in the ªDisabling the SRSº
procedure that follows, service can begin immediately
without waiting for the 15 second time period to expire.
Disabling The SRS
Removal
Turn the ignition switch to ªOFFº and turn the steering
wheel so that the vehicle's wheels are pointing straight
ahead.
1. Remove SRS fuse ªC±21º from left dash side lower
fuse block or disconnect battery.
2. Disconnect yellow 2±pin connector at the base of
steering column.
3. Remove glove box assembly; Refer to ªPassenger air
bag assembly replacementº in this section.
4. Disconnect passenger air bag assembly yellow 2±pin
connector behind the glove box assembly.
CAUTION: W i t h t h e ª C±21º fuse removed and
ignition switch ªON,º the ªAIR BAGº warning lamp
will be ªON.º This is normal operation and does not
indicate an SRS malfunction.
Enabling The SRS
Installation
Turn ignition switch to ªLOCKº and remove key.
1. Connect yellow 2±pin connector passenger air bag
assembly.2. Install glove box assembly. Refer to ªPassenger Air
Bag Assembly Replacementº in this section.
3. Connect yellow 2±pin connector at the base of the
steering column.
4. Install ªAIR BAGº fuse ªC±21º to left dash side lower
fuse block or connect battery.
Turn ignition switch to ªONº and verify that the ªAIR BAGº
warning lamp turn on 3.5 seconds and then turns ªOFF.º If
it does not operate as described, perform the ªSRS
Diagnostic System Checkº in this section.
Handling / Installation / Diagnosis
1. Air bag assembly should not be subjected to
temperatures above 93
C (200
F).
2. Air bag assembly, and SDM should not be used if they
have been dropped from a height of 100 centimeters
(3.28 feet) or more.
3. When a SDM is replaced, it must be oriented with the
arrow on the SDM pointing toward the front of the
vehicle. It is very important for the SDM to be located
flat on the mounting surface, parallel to the vehicle
datum line. It is important that the SDM mounting
surface is free of any dirt or other foreign material.
4. Do not apply power to the SRS unless all components
are connected or a diagnostic chart requests it, as
this will set a diagnostic trouble code.
5. The ªSRS Diagnostic System Checkº must be the
starting point of any SRS diagnostics. The ªSRS
Diagnostic System Checkº will verify proper ªAIR
BAGº warning lamp operation and will lead you to the
correct chart to diagnose any SRS malfunctions.
Bypassing these procedures may result in extended
diagnostic time, incorrect diagnosis, and incorrect
parts replacements.
Inspections Required After An Accident
CAUTION: C e r t a i n S R S c o mponents must be
replaced after a frontal crash involving air bag
deployment.
In all types of accidents regardless of ªAir Bagº
deployment, visually inspect all of the following
components and replace as required:
Ð Driver air bag assembly
Ð Passenger air bag assembly
Ð Driver pretensioner assembly
Ð Passenger pretensioner assembly
Ð Steering wheel
Ð SRS coil assembly
Ð Steering column
Ð Knee bolster and instrument panel mounting
attachments
Ð Driver seat and belt
Ð Passenger seat and belt
Ð SDM
SDM always should be checked according to ªSDM
Replacement Guidelines.º

RESTRAINT CONTROL SYSTEM 9J1±4
System Schematic
D09RW014
SRS Diagnostic System Check
The diagnostic procedures used in this section are
designed to find and repair SRS malfunctions. To get the
best results, it is important to use the diagnostic charts
and follow the sequence listed below:
A. Perform the ªSRS Diagnostic System Check.º
The ªSRS Diagnostic System Checkº must be the
starting point of any SRS diagnostics. The ªSRS
Diagnostic System Checkº checks for proper ªAIR
BAGº warning lamp operation, the ability of the SDM
to communicate through the ªSerial Dataº line and
whether SRS diagnostic trouble codes exist.
B. Refer to the proper diagnostic chart as directed by the
ªSRS Diagnostic System Check.º
The ªSRS Diagnostic System Checkº will lead you to
the correct chart to diagnose any SRS malfunctions.
Bypassing these procedures may result in extended
diagnostic time, incorrect diagnosis and incorrect
parts replacement.
C. Repeat the ªSRS Diagnostic System Checkº after any
repair or diagnostic procedures have been
preformed.
Performing the ªSRS Diagnostic System Checkº after
all repair or diagnostic procedures will ensure that the
repair has been made correctly and that no other
malfunctions exist
Circuit Description
When the ignition switch is first turned ªONº, ªIgnition 1º
voltage is applied from the ªC±21º fuse to the SDM at the
ªIgnition 1º input terminals ª12º. The SDM responds by
flashing the ªAIR BAGº warning lamp turn on 3.5 seconds,
while performing tests on the SRS.
Notes On System Check Chart:
1. The ªAIR BAGº warning lamp should turn on 3.5
seconds after ignition is first turned ªONº.
2. After the ªAIR BAGº warning lamp turn on 3.5
seconds, it should turn ªOFFº
3. This test checks for the proper operation of the
ªSerial Dataº line. This test will also determine
whether history diagnostic trouble codes are stored
and, if so, identify them.
4. Improper operation of the ªAIR BAGº warning lamp
is indicated. This test differentiates a warning lamp
stays ªONº condition from a warning lamp does not
come ªONº condition.
5. This test checks for proper operation of the ªSerial
Dataº line. This test will also identify the stored
diagnostic trouble codes and whether they are
current or history.
Diagnostic Aids:
The order in which diagnostic trouble codes are
diagnosed is very important. Failure to diagnose the

RESTRAINT CONTROL SYSTEM 9J1±8
Chart B ªAIR BAGº Warning Lamp Comes ªONº Steady
D09RW014
Circuit Description:
When the ignition switch is first turned ªONº, ªIgnition 1º
voltage is applied from the ªC±10º fuse to ªAIR BAGº,
warning lamp which is connected to ªSRS Warning
Lampº, terminal ª7º. The ªC±21º fuses apply system
voltage to the ªIgnition 1º inputs, terminals ª12º. The SDM
responds by turning on the ªAIR BAGº warning lamp 3.5
seconds. If ªIgnition 1º is less than 9 volts, the ªAIR BAGº
warning lamp will come ªONº solid with no DTCs set.
Chart Test Description:
Number(s) below refer to step number(s) on the
diagnostic chart.
2. This test checks for an open in the ªIgnition 1º circuit
to the SDM.
3. This test checks for the voltage of ªIGNITION 1º.
4. This test determines whether the malfunction is a
short to ground in IB04±WHT/RED.

RESTRAINT CONTROL SYSTEM 9J1±10
Chart C ªAIR BAGº Warning Lamp Does Not Come ªONº Steady
D09RW014
Circuit Description:
When the ignition switch is first turned ªONº, ªIgnition 1º
voltage is applied from the ªC±10º fuse to the ªAIR BAGº
warning lamp which is connected to ªSRS Warning
Lampº, terminal ª7º. The ªC±21º fuse apply system
voltage to the ªIgnition 1º inputs, terminals ª12º. The SDM
responds by turning on the ªAIR BAGº warning lamp 3.5
seconds. If ªIgnition 1º is more than 16 volts, the ªAIR
BAGº warning lamp will be still ªOFFº solid with no DTCs
set.
Chart Test description:
Number(s) below refer to step number(s) on the
diagnostic chart:
1. This test decides whether power is available to SDM
warning lamp power feed circuit.2. This test determines whether the voltage is present
in the warning lamp circuit.
3. This test determines if the malfunction is in the
instrument cluster.
4. This test checks for open in the warning lamp
circuitry.
5. This test isolates the IB04±WHT/RED circuit and
checks for a short in the IB04±WHT/RED circuit to
B+.
8. This test checks for a short from the SDM warning
lamppower feed circuit to ground.
9. This test determines whether the short to ground is
due to a short in the wiring.

9J1±11
RESTRAINT CONTROL SYSTEM
Chart C ªAIR BAGº Warning Lamp Does Not Come ªONº Steady
StepActionYe sNo
11. When measurements are requested in this chart,use
5±8840±0285±0 DVM with correct terminal adapter from
5±8840±0385±0.
2. Ignition switch ªOFF.º
3. Remove and inspect ªC±10º fuse (meter) to the ªAIR BAGº
warning lamp.
Is fuse good?
Go to Step 2Go to Step 7
21. Ignition switch ªOFF.º
2. Disconnect SRS coil and passenger air bag assemblies.
Yellow 2±pin connector located at base of steering column and
behind the glove box assembly.
3. Disconnect SDM.
4. Ignition switch ªON.º
5. Measure voltage on SDM harness connector from terminal ª7º
to terminal ª6º (ground).
Is system voltage present on terminal ª7º?
Go to Step 4Go to Step 3
31. Ignition switch ªOFF.º
2. Remove instrument meter cluster.
3. Check for proper connection to instrument cluster at
IB04±WHT/RED terminal.
4. If ok, then remove and inspect ªAIR BAGº bulb.
Is bulb good?
Go to Step 5
Replace bulb
Go to Step 6
41. Ignition switch ªOFF.º
2. Disconnect instrument meter cluster harness connector.
3. Ignition switch ªON.º
4. Measure voltage on SDM harness connector from terminal ª7º
to terminal ª6º (GROUND).
Is voltage 1 volt or less?
Go to Chart A
Replace SRS
harness
Go to Step 6
51. Install bulb.
2. Measure resistance from instrument meter cluster harness
connector IB04±WHT/RED terminal to SDM harness
connector terminal ª7º.
Is resistance 5.0 ohms or less?Service
instrument meter
cluster
Install instrument
meter cluster
Go to Step 6
Replace SRS
harness
Go to Step 6
6Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished?Repeat the ªSRS
Diagnostic
System Checkº
Go to Step 6
7Perform chart C.
Was this step finished?
Go to Step 8Go to Step 1
81. Replace ªC±10º fuse.
2. Ignition switch ªONº wait 10 Seconds then ignition switch ªOff.º
3. Remove and inspect ªC±10º fuse.
Is fuse good?
Install ªC±10º
fuse
Go to Step 10
Go to Step 9

RESTRAINT CONTROL SYSTEM 9J1±12
Chart C ªAIR BAGº Warning Lamp Does Not Come ªONº Steady (Cont'd)
StepNo Ye s Action
91. Disconnect SRS coil and passenger air bag assemblies.
Yellow 2±pin connectors located at base of steering column
and behind the glove box assembly.
2. Disconnect SDM.
3. Replace ªC±10º fuse.
4. Ignition switch ªONº wait 10 seconds.
5. Ignition switch ªOFFº.
6. Remove and inspection ªC±10º fuse.
Is fuse good?
InstallªC±10º fuse
Go to Chart A
Replace SRS
harness
Replace ªC±10º
fuse
Go to Step 10
10Reconnect all SRS components, ensure all components are
properly mounted.
Was this step finished?Repeat the ªSRS
Diagnostic
System Checkº
Go to Step 10