2002 ISUZU AXIOM Service Repair Manual

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±63
Special Tools
ILLUSTRATIONTOOL NO.
TOOL NAME
J-33939
Drive plate holder
J-33944-A
Drive plate puller
J-33944-4
Forcing screw
J-38424
Pulley puller pilot
J-8433
Pulley puller
J-24092-2
Pulley puller leg
ILLUSTRATIONTOOL NO.
TOOL NAME
J-33940-A
Pulley installer
J-8092
Drive handle

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

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±65
Circuit Diagram
D01R200010

1A±66
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
D01R200011

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±67
D01R200003

1A±68
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
D01R200004

HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
1A±69
D01R200009

1A±70
HEATING, VENTILATION AND AIR CONDITIONING (HVAC)
Functions and Features
Automatic air conditioning control unit
The control unit features a prominent control and display
panel that clearly shows air conditioner operational
settings (delivered air volume, air outlet location,
inside/outside air circulation, and set temperature).
Desired temperature can be set in ±17
C (1
F)
increments. The current setting appears on the digital
display.
Automatic temperature control
Vehicle interior temperature is maintained at the set level.
It is unaffected by changes in vehicle speed, outside air
temperature, and number of passengers.
Maximum cooling and heating
Moving the switch to the 18
C (65
F) position provides
maximum cooling. Moving the switch to the 32
C (90
F)
position provides maximum heating.
Automatic air flow control
Air flow is automatically and precisely regulated in
response to set temperature change and/or changes in
heater unit mixing door aperture.
Automatic air outlet selection
Appropriate air outlets (VENT, BE-LEVEL, FOOT, or
DEF) are selected in response to changes in outlet
temperatures. The mode switch permits manual selection
of the desired air outlet.
Air source (Fresh air intake from outside the
vehicle or recirculation of the air inside the vehicle)
selection
Automatic switching between outside air (FRESH),
recirculated inside air (RECIRC), or a combination of the
two (MIX) occurs in response to changes in outlet
temperatures.The intake switch permits manual
selection of the air source (FRESH or RECIRC). Mixing
of the two sources is not possible during manual
operation. When the defrost mode switch (DEF) is
pressed, the system automatically switches to outside air
intake.
Cooler start-up control
When the vehicle is parked in a hot area for an extended
period of time, the evaporator becomes hot. When the
cooler is turned on, hot air is blown into the vehicle until
the evaporator cools down. The cooler start-up control
prevents blower operation until the evaporator is able to
provide cool air.
Heater start-up control
When the vehicle is parked in a cold area for an extended
period of time, the heater core becomes cold. When the
heater is turned on, cold air is blown into the vehicle until
the heater core heats up. The heater start-up control
prevents blower operation to the air outlets until the
heater core is able to provide warm air. Air is delivered
through the defrost outlets.
Solar radiation offset
The sun sensor uses a photodiode to precisely determine
the amount of solar radiation affecting the vehicle. The
cooler operates in response to this radiation to quickly
correct the vehicle interior temperature.Switch position memory
Current switch positions are stored in memory when the
ignition switch is turned off. When the ignition switch is
turned on again, the switches automatically return to the
position they were in when the ignition switch was turned
off. This simplifies the restarting procedure.
Self-diagnosis function
The self-diagnosis switches on the control panel permit
easy system troubleshooting. Refer to ªSelf-Diagnosisº
later in this Section.