Scheme 2
| Item Number | Description |
|---|---|
| 1 | Sunlight sensor |
| 2 | In-vehicle temperature sensor |
| 3 | Automatic temperature control (ATC) module |
| 4 | Coolant valve |
| 5 | Auxiliary coolant pump |
| 6 | Refrigerant pressure sensor |
| 7 | Pollution sensor - TdV8 |
| 8 | Pollution sensor - 4.2L and 4.4L petrol |
| 9 | Evaporator temperature sensor |
| 10 | Steering wheel recirculation switch (where fitted) |
| 11 | Heater temperature sensor |
OVERVIEW
The air conditioning (A/C) control system automatically adjusts the temperature, volume and distribution of the air from the heater to maintain the individual temperature levels selected for the left-hand (LH) and right-hand (RH) sides of the cabin. The system also has manual overrides for the intake air source, blower speed and air distribution.
Some vehicles may be fitted with a 4 zone climate control system. Refer to Auxiliary Climate Control .
PRINCIPLES OF OPERATION
The system operates on the reheat principle. Air entering the heater assembly is cooled to a constant value by the evaporator and then reheated as necessary by the heater core to produce the temperature(s) selected on the control panel.
To determine the various system settings, the automatic temperature control (ATC) module derives a reference value (called the Y factor) from
- The temperature setting on the control panel.
- The ambient temperature.
- The in-vehicle temperature.
The reference value is measured in %, where -27.5% means maximum cooling is required and 100% means maximum heating is required. Separate reference values are produced for the left-hand (LH) and right-hand (RH) sides of the heater assembly.
The reference value is used for temperature control. The driver's side reference value is also used for door positioning and blower speed calculations.
When the ignition is turned off the automatic temperature control (ATC) module memorizes the system settings and resumes the same settings the next time the ignition is switched on.