2002 ISUZU AXIOM relay

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±13
Blower Link Unit and / or Mode door
Disassembled View
873R200001
Legend
(1) Blower Assembly
(2) Upper Case
(3) Mode Door
(4) Lower Case(5) Max High Relay
(6) Intake Actuator
(7) Sub Lever
(8) Door Lever
Removal
1. Disconnect the battery ground cable.
2. Discharge and recover refrigerant (with air
conditioning).

Refer to
Refrigerant Recovery in this section.
3. Remove blower assembly.

Refer to
Blower Assembly in this section.
4. Remove intake actuator.
5. Remove max high relay.
6. Remove lower case.
7. Separate the upper case and slit the lining parting
face with a knife.
873RS002

1A±30
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Chart ªAº Condenser Fan Does Not Run
StepActionYe sNo
1Are 30A fuse normal?Go to Step 2Replace
2Is relay (X-16) normal?Go to Step 3Replace
3Is pressure switch normal?
Go to Step 4
Switch defective
or insufficient
refrigerant.
4Is fan motor normal?Go to Step 5Replace
51. Disconnect condenser fan relay (X-16).
2. Check to see if battery voltage is present at the chassis side
relay terminal NO. X16-5.
Is there a battery voltage?
Go to Step 6
Repair open
circuit between
Condenser Fan
fuse (30A) and
No.X16-5.
61. Reconnect condenser fan relay (X-16).
2. Check to see if battery voltage is present at chassis side
connector terminal No.C21-3.
Is there a battery voltage?
Go to Step 7
Repair open
circuit between
fuse (10A) and
C21-3.
7Check to see if continuity between chassis side relay terminal
No.X16-2 and the chassis side connector terminal No.C21-4.
Is there a continuity?
Go to Step 8
Repair open
circuit.
8Check to see if continuity between chassis side connector
terminal No. C16-1 and chassis side relay terminal No.X16-1.
Is there a continuity?Poor ground or
open circuit
between chassis
side connector
terminal
No.X16-4 (or
No.C16-2) and
body ground
(No.C10).
Repair open
circuit.
Chart ªBº Condenser Fan Does Not Stop
StepActionYe sNo
11. Disconnect the triple pressure connector.
Does condenser fan stop?
Replace the triple
pressure switch.
Replace the
condenser fan
relay.

1A±64
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Automatic Air Conditioning System
General Description
Using a variety of sensors, this automatic air conditioner
accurately senses outside air temperature, solar
radiation quantity, evaporator's blowing temperature, and
interior temperature, then enters these data to the
automatic air conditioner control unit (equipped with the
built-in micro-computer). The data provided to the control
unit enables to automatically control blow temperatureand blow air quantity, turn on or off the compressor and
switch the blow port as well as switching between the
fresh air intake and interior air circulation.
Resetting the automatic function allows you to switch to
the manual control mode.
The self-diagnoisis function of the automatic air
conditioner control unit (with the built-in micro-computer)
allows the unit to access and diagnose a failed part easier
and quicker.
Automatic Air Conditioner Parts Configuration
865R200050
Legend
(1) In Car Sensor
(2) Sun Sensor
(3) Ambient Sensor
(4) Intake Actuator
(5) Blower Unit
(6) Max ± High Relay
(7) Display(8) Audio & Switch Assembly
(9) Evaporator Assembly
(10) Duct Sensor
(11) Mix Actuator
(12) Heater Unit
(13) Automatic Air Conditioner Control Unit
(14) Mode Actuator

1A±78
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Sun Sensor
It is a photodiode used for detecting quantity of solar
radiation. This sensor converts the offset signal
generated by changes in the interior temperature (which
results from fluctuations in solar radiation) into
photoelectric current to enter into the automatic air
conditioner control unit.
This sensor is provided at top of the center cluster upper.
865R200002
Legend
(1) Sun Sensor
(2) Center Cluster Upper
Power Transistor
Receiving base current from the automatic air conditioner
control unit, the power transistor implements stage-less
speed change of the blower fan motor. This transistor is
provided on the evaporator.
874R200009
Legend
(1) Evaporator Assembly
(2) Power Transistor
Max Hi Relay
This relay turned on or off by the signal from the automatic
air conditioner control unit. As the Max Hi relay is turned
on, supply voltage is directly fed to the blower fan motor to
select the Max Hi mode.
873RY00005
Legend
(1) Blower Unit
(2) Max High Relay

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±83
Interior Temperature Control
When the temperature control switch is set to a specific
temperature, a signal is sent to the A/C control unit. Other
signals are sent to the control unit from the various
sensors. This data is analyzed by the control unit which
creates a composite data signal that is compared with the
signal received from the potentiometer. The result
determines the direction of mix actuator rotation.
The mix actuator reacts to the composite air mix door
opening angle signal. Opening angle is increased or
decreased to maintain the temperature at the selected
level.
When the compressor is off, the air mix door moves
toward the COOL side. When the compressor turns on,
the temperature of the air being discharged from the
outlet vents is regulated.
When the temperature control is set to 18
C (65
F), the
air mix door moves to the FULL COOL position. When the
control is set to 32
C (90
F), the door moves to the FULL
HOT position.
In the VENT position, the air mix door moves from FULL
COOL to a 60% aperture. This prevents hot air from being
discharged into the vehicle.
C01R200005
Air Flow Control
In the Auto Mode

Automatic operation
When the AUTO switch or the DEF switch is pressed, a
signal indicating the forced air volume is sent to the A/C
auto-control unit. Other signals are sent to the control
unit from the various sensors. This data is analyzed by
the control unit which creates a composite data signal.
Based on this signal, the base voltage of the power
transistor is varied to change the blower voltage. This
results in a non-stepped change in blower motor
speed.
When the temperature control switch is set to either
18
C (65
F) or 32
C (90
F), blower motor speed is in
the MAX-HI mode.
In the Manual Mode

Manual operation
When the fan switch is manually set to a specified air
volume, a signal is sent to the A/C auto-control-unit. In
response to this signal, the auto-control unit controls
the blower voltage.
When the fan switch is set to HI, the max-hi relay
operates to increase blower motor speed to the
MAX-HI mode.
C01R200001

1A±102
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
ConditionPossible causeCorrection
Does not work at allÐRefer to Chart A
Control failureÐRefer to Chart B
Chart A: Does Not Work At All
StepActionValue(s)Ye sNo
1Is the fuse FL±1 normal?
ÐGo to Step 2
Replace the
fuse
2Is the fuse F±7 normal?
ÐGo to Step 3
Replace the
fuse
3Is the relay X±1 normal?
ÐGo to Step 4
Replace the
relay
4Turn on the ignition switch. (the engine is run.)
Is the battery voltage applied between the harness side
connector terminal No.C33±3 and ground?
Approx 12VGo to Step 6Go to Step 5
5Repair an open circuit between terminal No.C33±3 and
No.X1±1.
Is the action complete?
ÐGo to Step 4Ð
6Is the battery voltage applied between the harness side
connector terminal No.C33±4 and ground?
Approx 12VGo to Step 8Go to Step 7
7Replace the intake actuator motor.
Is the action complete?
ÐGo to Step 6Ð
8Is there continuity between the harness side connector
terminal No.I19±11 and No.C33±4?
ÐGo to Step 10Go to Step 9
9Repair an open circuit between No.I19±11 and C33±4.
Is the action complete?
ÐVerify repairÐ
10Replace the auto air conditioner control unit.
Is the action complete?
ÐVerify repairÐ

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±103
Chart B: Failure on the Intake Control
StepActionValue(s)Ye sNo
1Is the fuse No.F±7 normal?
ÐGo to Step 2
Replace the
fuse
2Is the relay No.X±1 normal?
ÐGo to Step 3
Replace the
relay
3Turn on the ignition switch. (the engine is run.)
Is the intake actuator stopped?
ÐGo to Step 5Go to Step 4
4Replace or repair the auto air conditioner control unit.
Is the action complete?
ÐVerify repairÐ
5Is there continuity between the harness side connector
terminal No.C33±5 and No.I20±11?
ÐGo to Step 7Go to Step 6
6Repair an open circuit between terminal No.C33±5 and
No.I20±11.
Is the action complete?
ÐGo to Step 5Ð
7Is there continuity between the harness side connector
terminal No.C33±6 and No.I20±12?
ÐGo to Step 9Go to Step 8
8Repair an open circuit between terminal No.C33±6 and
No.I20±12.
Is the action complete?
ÐGo to Step 7Ð
9Is there continuity between the harness side connector
terminal No.C33±1 and No.I20±13?
ÐGo to Step 11Go to Step 10
10Repair an open circuit between terminal No.C33±1 and
I20-13.
Is the action complete?
ÐGo to Step 9Ð
11Is there continuity between the harness side connector
terminal No.C33±2 and No.I20±14?
ÐGo to Step 13Go to Step 12
12Repair an open circuit between harness No.C33±2 and
No.I20±14.
Is the action complete?
ÐGo to Step 11Ð
131. Disconnect the intake actuator connector No.C33.
2. Is the battery voltage applied between harness side
connector terminal
No.C33±6 and ground?
No.C33±2 and ground?
No.C33±1 and ground?
ÐGo to Step 14Go to Step 15
14Replace or repair the intake actuator.
Is the action complete?
ÐVerify repairÐ
15Replace or repair the air conditioner control unit.
Is the action complete?
ÐVerify repairÐ

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±111
ConditionPossible causeCorrection
The fan dose not rotate at allÐRefer to Chart A
The fan dose not rotate in the
MAX±HI modeÐRefer to Chart B
The fan dose not rotate in any mode
other than MAX±HIÐRefer to Chart C
The fan dose not stopÐRefer to Chart D
Chart A: Fan Does Not Rotate At All
StepActionValue(s)Ye sNo
1Are the fuse No.F±5, F±6 and No.F±7 normal?
ÐGo to Step 2
Replace the
fuse
2Are the relay No.X±1 and No.C±35 normal?
ÐGo to Step 3
Replace the
relay
3Turn on the ignition switch (the engine is run).
Is the battery voltage applied between the harness side
connector terminal No.C36±1 and ground?
ÐGo to Step 5Go to Step 4
4Repair an open circuit between terminal No.C36±1 and
No.F±5 and F±6 fuse.
Is the action complete?
ÐGo to Step 3Ð
5Is there continuity between the harness side connector
terminal No.C36±2 and ground (No.C±10)?
ÐGo to Step 7Go to Step 6
6Repair an open circuit between terminal No.C36±2 and
ground.
Is the action complete?
ÐÐÐ
7Is the battery voltage applied between the harness side
connector terminal No.C36±2 and No.C36±1?
ÐGo to Step 8Go to Step 9
8Replace the blower motor.
Is the action complete?
ÐVerify repairÐ
9Refer to chart B and C.
Is the action complete?
ÐVerify repairÐ