Description

AIR CONDITIONER CONTROL

Description
The front air control provides automatic regulation of the vehicle's interior temperature. The system is based on the driver's and passenger's selected "set temperature", regardless of the outside temperature changes. This is done by utilizing a microcomputer, also referred to as the front air control, which receives input signals from the following seven sensors:
- Ambient sensor
- In-vehicle sensor
- Intake sensor
- Optical sensor (one sensor for driver and passenger side)
- PBR (Position Balanced Resistor) built into the mode door motor, air mix door motors, and defroster door motor.
- Vehicle speed sensor
- Engine coolant temperature

The front air control uses these signals (including the set temperature) to automatically control:
- Outlet air volume
- Air temperature
- Air distribution

The front air control is used to select:
- Outlet air volume
- Air temperature/distribution

Operation

AIR MIX DOORS CONTROL
The air mix doors are automatically controlled so that in-vehicle temperature is maintained at a predetermined value by the temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.

BLOWER SPEED CONTROL
Blower speed is automatically controlled by the temperature setting, ambient temperature, in-vehicle temperature, intake temperature, amount of sunload and air mix door position.
When AUTO switch is pressed, the blower motor starts to gradually increase air flow volume (if required).
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flowing.

INTAKE DOOR CONTROL
The intake door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temperature, intake temperature, amount of sunload and by the ON-OFF operation of the compressor.

MODE DOOR CONTROL
The mode door is automatically controlled by the temperature setting, ambient temperature, in-vehicle temperature, intake temperature and amount of sunload.

DEFROSTER DOOR CONTROL
The defroster door is controlled by turning the defroster dial to front defroster.




MAGNET CLUTCH CONTROL
When A/C switch or DEF switch is pressed, front air control inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM and front air control, via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sensor signal, throttle angle sensor, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to IPDM E/R, via CAN communication line.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate compressor.

SELF-DIAGNOSTIC SYSTEM
The self-diagnostic system is built into the front air control to quickly locate the cause of certain symptoms. Refer to ATC-58, "A/C System Self-diagnosis Function". Reading and Clearing Diagnostic Trouble Codes