1998 ISUZU TROOPER fuse

SERVICE INFORMATION 00 Ð 35
MAGNETIC CLUTCH DOES NOT RUN
·TURN THE STARTER SWITCH ON AND START THE
ENGINE.
·TURN THE FAN SWITCH ON.
·DOES THE BLOWER MOTOR RUN?
YESNO
REFER TO THE DIAGNOSIS PROCEDURE FOR
ÒBLOWER MOTOR DOES NOT RUNÓ.·IS THE FUSE C-20 (10A) NORMAL?
YESNO
REPLACE THE FUSE.·DISCONNECT THE A/C SWITCH CONNECTOR AND
REMOVE THE A/C SWITCH.
·IS THE A/C SWITCH NORMAL?
YESNO
YESNO
REPAIR AN OPEN CIRCUIT BETWEEN THE
FUSE C-20 AND I23-2.·REINSTALL THE A/C SWITCH AND DISCONNECT THE DUAL
PRESSURE SWITCH (OR TRIPLE PRESSURE SWITCH) CON-
NECTOR C25.
·TURN THE A/C SWITCH ON.
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR C25-1?
YESNO
REPLACE THE SWITCH.·RECONNECT THE CONNECTOR C25 AND DISCONNECT THE
A/C THERMO RELAY CONNECTOR X5.
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CONNEC-
TOR C25-2 AND X5-1?
YESNO
REPAIR AN OPEN CIRCUIT BETWEEN I23-6
AND C25-1.·IS THE DUAL PRESSURE SWITCH (OR TRIPLE PRESSURE
SWITCH) NORMAL?
YESNO
REPAIR OR REPLACE THE SWITCH.·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR I23-2?

00 Ð 36 SERVICE INFORMATION
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR X5-2?REPAIR AN OPEN CIRCUIT.
YESNO
·IS THE A/C THERMO RELAY NORMAL?REPAIR AN OPEN CIRCUIT BETWEEN THE
FUSE C-20 AND X5-2.
YESNO
·DISCONNECT THE ELECTRONIC THERMOSTAT CONNEC-
TOR I42.
·IS THE BATTERY VOLTAGE APPLIED AT HARNESS SIDE
CONNECTOR I42-3?
YESNO
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CON-
NECTOR X5-3 AND I42-1?REPAIR AN OPEN CIRCUIT BETWEEN I23-6
AND I42-3.
YESNO
REPAIR AN OPEN CIRCUIT.
YESNO
·IS THERE CONTINUITY BETWEEN HARNESS SIDE CON-
NECTOR I42-2 AND THE GROUND?REPAIR AN OPEN CIRCUIT.
REPLACE THE RELAY.
·DIS CONNECT THE MAGNETIC CLUTCH CONNECTOR E27.
·CONNECT THE BATTERY WITH MAGNETIC CLUTCH SIDE
CONNECTOR E27-1.
·DOES THE MAGNETIC CLUTCH.
YESNO
REPAIR OR REPLACE THE MAGNETIC CLUTCH.·REPAIR AN OPEN CIRCUIT BETWEEN X5-4 AND E27-1.

00 Ð 38 SERVICE INFORMATION
CONDENSER FAN DOES NOT RUN
YESNO
·DOES A/C SYSTEM OPERATE CORRECTLY?
·IS FL-4 (30A) FUSE OK?CHECK A/C SYSTEM AND REPAIR AS NECESSARY
YESNO
·IS CONDENSER FAN RELAY (X-19) OK?REPLACE
REPLACE
YESNO
·IS TRIPLE PRESSURE SWITCH (CYCLING SWITCH SIDE)
OK?
REPLACE
YESNO
·IS CONDENSER FAN MOTOR OK?
REPLACE
YESNO
·CHECK TO SEE IF CONTINUITY BETWEEN FL-4 (30A)
FUSE AND CHASSIS SIDE RELAY TERMINAL NO. X19-1.
REPLACE
YESNO
·CHECK TO SEE IF CONTINUITY BETWEEN CHASSIS SIDE
CONNECTOR TERMINAL NO. I23-6 AND NO. C25-3.
OPEN CIRCUIT
YESNO
·CHECK TO SEE IF CONTINUITY BETWEEN CHASSIS SIDE
CONNECTOR TERMINAL NO. C25-4 AND CHASSIS SIDE
RELAY TERMINAL NO. X19-4.
OPEN CIRCUIT
YESNO
·CHECK TO SEE IF CONTINUITY BETWEEN CHASSIS SIDE
RELAY TERMINAL NO. X19-5 AND CHASSIS SIDE
CONNECTOR TERMINAL NO. I18-4.
OPEN CIRCUIT
YESNO

AIR CONDITIONING 1BÐ113
Inspection of the Fan Motor System
H-26
10 11 12 13 14 151234 5
17 18 19 206789
16
9876
20 19 18 17 165
14 154
133
122
111
10
H-20
I-32I-33
12345678
9 101112131415161
112
123
134
145
156
167
178
189
1910
20
B-1B-5I-50B-36
12
34
I-33
M
17
19
I-50 2
0.3 GR
2.0L/B
I-50
I-501
3
B-52
B-5
1
I-512
41
3
B-12.0 B1
2 B
2 L/B
0.3 BR
0.5 L/B2 L/B
2 B
0.3 GR/L 123.0 L 3.0 L/R
C-19 25A
FUSE
C-20 10A
FUSE
Blower Motor
Max High
Relay Power
Transistor Auto A/C
Control Unit
B-36
I-51
I-51 I-51
I-32 I-33
12
33 14
H-20
H-2610
1
2
I-51
2
34 11
23
H-202
241
312
34
D08RY00181

AIR CONDITIONING 1BÐ119
Chart A: Magnet Clutch Does Not work
NOThe harness is disconnected.
NOReplace the failed relay.
NOFailure on the power supply system.
NO
NO
NOReplace the fuse.
YESFailure on the magnet clutch.
NOReplace the electronic thermostat.
YES
YES YES
YES
YESNO
YES
The harness is disconnected.
Failure on the pressure switch or
refrigerant is insufficient.
Turn the A/C (air conditioner) switch on.
Are the pressure switch side connector
terminals No.1 and No.2
conducted?C-25C-25
Are relays normal?
Is fuse (C-20) 10A normal?
Is the electronic thermostat normal?
Is the battery voltage present between
the chassis harness side connector
terminal No.1 and the ground?
E-3
Is the battery voltage present between
the chassis harness side connector
terminal No.1 and the ground.
C-25
Is the battery voltage present between
the chassis side relay terminal No.3
and the ground, and No.1
and the ground?
X-7X-5
YES
Turn the ignition switch off.
Is conduction provided between the
following chassis harness side connecter
terminals?
No.2 and No.2 .
No.4 and No.1 .
E-3X-7
X-7X-5
Turn the ignition switch on (the engine is
started).
Magnet clutch does not work
Chart A
Type of trouble

1BÐ122 AIR CONDITIONING
Chart A: Magnet Clutch Does Not Work
NOReplace the fuse.
NOReplace the failed relay.
NOReplace the electronic thermostat.
YESFailure on the magnet clutch.
NOThe harness is disconnected.
NOFailure on the power supply system.
YES
Is fuse C-20 (10A) normal?
Are relays normal?
YES
YES
Is the electronic thermostat normal?
YES
Turn the A/C (air conditioner) switch on.
Is the battery voltage present between the
chassis harness side connector terminal
No.1 and the ground?
E-27
NO
Is the battery voltage present between the
chassis harness side connector terminal
No.1 and the ground.
C-25
YES
NOFailure on the pressure switch or refrigerant is
insufficient.
NOThe harness is disconnected.Is the battery voltage present between the
chassis side relay terminal No.1
and the ground?X-5
Are the pressure switch side connector
terminals No.1 and No.2
conducted?C-25C-25
YES
YES
Failure on the automatic heater/air
conditioner control unit.
NOThe harness is disconnected.
Is conduction provided between the
chassis harness side connecter terminals
No.1 and No.4 ?
X-5E-27
YES
Are the chassis harness connector
terminals No.14 and No.3 ?X-5I-32

DIFFERENTIAL (REAR 220mm)
4A2A±3
Diagnosis
Many noises that seem to come from the rear axle
actually originate from other sources such as tires, road
surface, wheel bearings, engine, transmission, muffler, or
body drumming. Investigate to find the source of the
noise before disassembling the rear axle. Rear axles, like
any other mechanical device, are not absolutely quiet but
should be considered quiet unless some abnormal noise
is present.
To make a systematic check for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct level,
and then drive the vehicle far enough to thoroughly
warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run the
engine speed slowly up and down to determine if the
noise is caused by exhaust, muffler noise, or other
engine conditions.
4. Tire noise changes with different road surfaces; axle
noises do not. Temporarily inflate all tires to 344 kPa
(3.5kg/cm
2, 50 psi) (for test purposes only). This will
change noise caused by tires but will not affect noise
caused by the rear axle.
Rear axle noise usually stops when coasting at
speeds under 48 km/h (30 mph); however, tire noise
continues with a lower tone. Rear axle noise usually
changes when comparing pull and coast, but tire
noise stays about the same.
Distinguish between tire noise and rear axle noise by
noting if the noise changes with various speeds or
sudden acceleration and deceleration. Exhaust and
axle noise vary under these conditions, while tire
noise remains constant and is more pronounced at
speeds of 32 to 48 km/h (20 to 30 mph). Further check
for tire noise by driving the vehicle over smooth
pavements or dirt roads (not gravel) with the tires at
normal pressure. If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause noise
which may be confused with rear axle noise; however,
front wheel bearing noise does not change when
comparing drive and coast. Light application of the
brake while holding vehicle speed steady will often
cause wheel bearing noise to diminish. Front wheel
bearings may be checked for noise by jacking up the
wheels and spinning them or by shaking the wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when correctly
installed. Check to see that there is no link or rod
loosened or metal±to±metal contact.
7. Make sure that there is no metal±to±metal contact
between the floor and the frame.
After the noise has been determined to be in the axle, the
type of axle noise should be determined, in order to make
any necessary repairs.
Gear Noise
Gear noise (whine) is audible from 32 to 89 km/h (20 to 55
mph) under four driving conditions.
1. Driving under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle from
driving the engine while the vehicle slows down
gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the throttle
closed. The gear noise is usually more noticeable
between 48 and 64 km/h (30 and 40 mph) and 80 and
89 km/h (50 and 55 mph).
Bearing Noise
Bad bearings generally produce a rough growl or grating
sound, rather than the whine typical of gear noise.
Bearing noise frequently ªwow±wowsº at bearing rpm,
indicating a bad pinion or rear axle side bearing. This
noise can be confused with rear wheel bearing noise.
Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in neutral. Noise
may diminish by gentle braking. Jack up the rear wheels,
spin them by hand and listen for noise at the hubs.
Replace any faulty wheel bearings.
Knock At Low Speeds
Low speed knock can be caused by worn universal joints
or a side gear hub counter bore in the cage that is worn
oversize. Inspect and replace universal joints or cage and
side gears as required.
Backlash Clunk
Excessive clunk on acceleration and deceleration can be
caused by a worn rear axle pinion shaft, a worn cage,
excessive clearance between the axle and the side gear
splines, excessive clearance between the side gear hub
and the counterbore in the cage, worn pinion and side
gear teeth, worn thrust washers, or excessive drive pinion
and ring gear backlash. Remove worn parts and replace
as required. Select close±fitting parts when possible.
Adjust pinion and ring gear backlash.

DIFFERENTIAL (REAR 244mm)
4A2B±3
Diagnosis
Many noises that seem to come from the rear axle
actually originate from other sources such as tires, road
surface, wheel bearings, engine, transmission, muffler, or
body drumming. Investigate to find the source of the
noise before disassembling the rear axle. Rear axles, like
any other mechanical device, are not absolutely quiet but
should be considered quiet unless some abnormal noise
is present.
To make a systematic check for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct level,
and then drive the vehicle far enough to thoroughly
warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run the
engine speed slowly up and down to determine if the
noise is caused by exhaust, muffler noise, or other
engine conditions.
4. Tire noise changes with different road surfaces; axle
noises do not. Temporarily inflate all tires to 344 kPa
(3.5kg/cm
2, 50 psi) (for test purposes only). This will
change noise caused by tires but will not affect noise
caused by the rear axle.
Rear axle noise usually stops when coasting at
speeds under 48 km/h (30 mph); however, tire noise
continues with a lower tone. Rear axle noise usually
changes when comparing pull and coast, but tire
noise stays about the same.
Distinguish between tire noise and rear axle noise by
noting if the noise changes with various speeds or
sudden acceleration and deceleration. Exhaust and
axle noise vary under these conditions, while tire
noise remains constant and is more pronounced at
speeds of 32 to 48 km/h (20 to 30 mph). Further check
for tire noise by driving the vehicle over smooth
pavements or dirt roads (not gravel) with the tires at
normal pressure. If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause noise
which may be confused with rear axle noise; however,
front wheel bearing noise does not change when
comparing drive and coast. Light application of the
brake while holding vehicle speed steady will often
cause wheel bearing noise to diminish. Front wheel
bearings may be checked for noise by jacking up the
wheels and spinning them or by shaking the wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when correctly
installed. Check to see that there is no link or rod
loosened or metal±to±metal contact.
7. Make sure that there is no metal±to±metal contact
between the floor and the frame.
After the noise has been determined to be in the axle, the
type of axle noise should be determined, in order to make
any necessary repairs.
Gear Noise
Gear noise (whine) is audible from 32 to 89 km/h (20 to 55
mph) under four driving conditions.
1. Driving under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle from
driving the engine while the vehicle slows down
gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the throttle
closed. The gear noise is usually more noticeable
between 48 and 64 km/h (30 and 40 mph) and 80 and
89 km/h (50 and 55 mph).
Bearing Noise
Bad bearings generally produce a rough growl or grating
sound, rather than the whine typical of gear noise.
Bearing noise frequently ªwow±wowsº at bearing rpm,
indicating a bad pinion or rear axle side bearing. This
noise can be confused with rear wheel bearing noise.
Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in neutral. Noise
may diminish by gentle braking. Jack up the rear wheels,
spin them by hand and listen for noise at the hubs.
Replace any faulty wheel bearings.
Knock At Low Speeds
Low speed knock can be caused by worn universal joints
or a side gear hub counter bore in the cage that is worn
oversize. Inspect and replace universal joints or cage and
side gears as required.
Backlash Clunk
Excessive clunk on acceleration and deceleration can be
caused by a worn rear axle pinion shaft, a worn cage,
excessive clearance between the axle and the side gear
splines, excessive clearance between the side gear hub
and the counterbore in the cage, worn pinion and side
gear teeth, worn thrust washers, or excessive drive pinion
and ring gear backlash. Remove worn parts and replace
as required. Select close±fitting parts when possible.
Adjust pinion and ring gear backlash.