1998 ISUZU TROOPER ignition

1BÐ94 AIR CONDITIONING
Chart "A" : Check of Auto Amplifier Power Supply System
NOHarness disconnection or improper grounding.
NOHarness disconnection or improper grounding.
NOHarness disconnection or trouble on lighting
switch.
NOHarness disconnection or improper grounding.
Turn off ignition switch.
Power supply system is free of
trouble.
YES YES
YES YES
Is battery voltage present between chassis
harness connector terminal No.7
and ground?
I-32
Is battery voltage present between
chassis harness connector No.8
and ground?
I-32
Are chassis harness connector No.16
and body ground conducted?
B-18I-32
Turn on ignition switch (engine is started).
Turn on lighting switch.
Is battery voltage present between chassis
harness connector No.10 and
ground?
I-32

AIR CONDITIONING 1BÐ97
TROUBLESHOOTING WITH SELF-DIAGNOSIS FUNCTION
1. Overview of Self-Diagnosis Function
The self-diagnosis is implemented in 3 steps for each target. For detail of check procedure contained in
each step, refer to the relevant section of "Check Procedure by Failed Location" listed in the Self-
Diagnosis Operation Procedure.
For turning on the self-diagnosis function and switching of the check step, refer to the flow chart given
below. You can reset the self-diagnosis function by turning the ignition switch off or turning the DEF
switch on for 3 seconds.
2. Self-Diagnosis Operation Procedure
While holding both the Auto switch and the DEF switch on the
automatic heater/air conditioner panel, turn the IG off and then
on.

Does the A/C LED flash every 0.5 second interval?
Press the A/C switch once.
(The past trouble
diagnosing function will
be turned on.)

Does the A/C LED flashes every 0.5 seconds?

Does each output equipment functions normally according to
operation of the temperature setting lever?
Press the DEF switch for 3
seconds consecutively or turn on
and off the IG.
Failure on the
output equipment
or the harness.
Preparations
(1) Set the IG to the OFF mode.
(2) Apply 60W bulb light to the sun sensor.
(3) Set the temperature setting lever on the automatic heater/air
conditioner panel to the center position (25C).
(4) Set the fan switch on the same panel to the Auto position.
End of the self-diagnosis.(The current trouble diagnosing function will be turned on
approximately in 10 seconds.)
YESNO
YESNO
NO
YES
Refer to *1.
Refer to *2.

AIR CONDITIONING 1BÐ105
Chart A: Does Not Work At All
NOFailure on the power supply circuit.
NOFailure on the actuator.
NOThe harness is disconnected.
NOReplace the automatic heater/air conditioner
control unit.
YES
YES YES
YES
Turn on the ignition switch (the engine is
started).
Switch between the fresh air intake and the
interior air circulation.
Failure on the intake link unit (intake door
lock).
Is the battery voltage present between the
chassis harness side connector terminal
No.3 and the ground?
I-49
Is the battery voltage present between
the chassis harness side connector
terminal No.4 and the ground?
I-49
Is the battery voltage present between
the chassis harness side connector
terminal No.11 and the ground?
I-32
During the above switch operations, did
the voltage between the chassis harness
side connector terminal No.11 and
the ground go below 0.5V?
I-32

1BÐ106 AIR CONDITIONING
Chart B: Failure on the Intake Control
NOThe harness is disconnected.
NOFailure on the automatic heater/air
conditioner control unit.
NOFailure on the automatic heater/air
conditioner control unit.
YES YES
YES
Turn on the ignition switch (the engine is
started).
Disconnect the intake actuator connector
(I-49).
Failure on the intake actuator.
Is the intake actuator stopped?
Is conduction provided between the
following chassis harness side connector
terminals?
No.5 and No.11 .
No.6 and No.12 .
No.1 and No.13 .
No.2 and No.14 .
I-33I-49
I-33I-49
I-33I-49
I-33I-49
Is voltage (approximately 5V) present
between the following?
No.12 and the ground.
No.13 and the ground.
No.14 and the ground.
I-33
I-33
I-33

1BÐ108 AIR CONDITIONING
Chart A: Does Not work At All
NOThe harness is disconnected.
NOReplace the automatic heater/air
conditioner control unit.
NOReplace the automatic heater/air
conditioner control unit.
YES YES
YES
Turn on the ignition switch (the engine is
started).
Disconnect the mix actuator connector
.
Short-circuit he chassis harness side
connector terminal No.3 and No.7
.
I-45I-45
I-45
Using the temperature control lever,
select FC for the temperature.
Using the temperature control lever,
select FC for the temperature.
Failure on the actuator.
Is the battery voltage present on a regular
interval basis between the chassis
harness side connector terminals No.6
(+) and No.5 (-)?
I-32I-32
Is conduction provided between the
following chassis harness side connector
terminals?
No.6 and No.6 .
No.5 and No.8 .
I-45I-32
I-45I-32
Is the battery voltage present on a regular
interval basis between the chassis
harness side connector terminals No.6
(-) and No.5 (+)?
I-32I-32

AIR CONDITIONING 1BÐ109
Chart B: Mix Actuator Control Failure
NOReplace the actuator.
NOThe harness is disconnected.
NO
NOMix actuator control failure due to the
failed sensor.
YES YES
YES
YES
Turn on the ignition switch (the engine is
started).
Replace the automatic heater/air conditioner
control unit.
Is conduction provided between the
following chassis harness side
connector terminals?
No.3 and No.11 .
No.7 and No.5 .
No.2 and No.15 .
I-33I-45
I-33I-45
I-33I-45
Is sum of the voltages between the
following chassis harness side connector
terminals approximately 5V?
Voltage between No.15 and No.5
plus voltage between No.5
and No.11 .
I-33
I-33I-33
I-33
Does the self-diagnosis function (the
current trouble display) indicate failure
on the mix actuator potentiometer?
Is full stroke of the air mix door available
when you selected FH or FC using the
temperature control lever?Failure on the air mix door or the link
unit.

AIR CONDITIONING 1BÐ111
Chart A: Does Not Work At All
NOThe harness is disconnected.
NOReplace the automatic heater/air
conditioner control unit.
NOReplace the automatic heater/air
conditioner control unit.
YES YES
YES
Turn on the ignition switch (the engine is
started).
Disconnect the mode actuator connector
(B-69).
Select VENT pushing the mode actuator
switch.
Turn on the DEF mode switch.
Failure on the actuator.
Is the battery voltage provided on a
regular interval between the following
chassis side connector terminals?
No.3 (+) and No.4 (-).
I-32I-32
Is conduction provided between the
following chassis harness side connector
terminal?
No.1 and No.4 .
No.5 and No.3 .
I-32B-69
I-32B-69
Is the battery voltage provided on a
regular interval between the following
chassis harness side connector
terminals?
No.4 (+) and No.3 (-).
I-32I-32

1BÐ112 AIR CONDITIONING
Chart B: Mode Actuator Control Failure
NOThe harness is disconnected.
NOReplace the actuator.
NOFailure on the mode door or the link unit.
YESMode control failure due to the failed
sensor.
NO YES
YES
YES
Turn on the ignition switch (the engine is
started).
Replace the automatic heater/air conditioner
control unit.
Is conduction provided between the
following chassis harness side
connector terminals?
No.9 and No.11 .
No.3 and No.10 .
No.4 and No.8 .
I-33B-69
I-33B-69
I-33B-69
Is sum of the voltages between the
following chassis harness side connector
terminals approximately 5V?
Voltage between No.15 and No.1
plus voltage between No.15
and No.11 .
I-33
I-32I-32
I-32
Does the mode work normally through
manual operation?
Is full stroke available from the mode
door when the defrost mode and vent
mode are selected?