Dual pressure switch nominal operating pressures (Air conditioning)

RH temperature. Illuminates to show the RH temperature selection, external air temperature or diagnostic fault code.

Blower speed. Illuminates when the blower speed is manually selected. Also illuminates in the automatic modes when one of the temperatures is set to LO or HI.

External air temperature. EXT illuminates to show that external air temperature is selected on.

All temperature indications on the display are in either °C or °F. For 1 second after the system is first switched on, the display shows only °C or °F, in the LH temperature window, to indicate which temperature scale is in use. After 1 second, the °C or °F indication goes off and the display shows all relevant outputs.

Temperature conversion: While the system is on, the temperature indications on the display can be switched between the two scales by pressing and holding the fresh/recirculated air switch, then pressing and holding the A/C on/off switch until the audible warning sounds (approximately 3 seconds).

Dual pressure switch The dual pressure switch protects the refrigerant system from extremes of pressure. The normally closed switch is installed in the top of the receiver drier. If minimum or maximum pressure limits are exceeded the switch contacts open, causing the compressor clutch to be disengaged. The minimum pressure limit protects the compressor, by preventing operation of the system unless there is a minimum refrigerant pressure (and thus refrigerant and lubricating oil) in the system. The maximum pressure limit keeps the refrigerant system within a safe operating pressure.

Dual pressure switch nominal operating pressures

Evaporator temperature sensor The evaporator temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input of the evaporator air outlet temperature. The evaporator temperature sensor is installed in a clip which locates in the evaporator matrix in the heater assembly. The ATC ECU uses the input to prevent the formation of ice on the evaporator.

In-car temperature sensor The in-car temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input of cabin air temperature. The sensor is integrated into the inlet of an electric fan, which is installed behind a grille in the fascia outboard of the steering column. The fan runs continuously, while the ignition is on, to draw air through the grille and across the sensor.

Sunlight sensor The sunlight sensor consists of two diodes that provide the ATC ECU with inputs of light intensity, one as sensed coming from the left of the vehicle and one as sensed coming from the right. The inputs are used as a measure of the solar heating effect on vehicle occupants. The sensor is installed in the centre of the fascia upper surface.

Heater coolant temperature sensor The heater coolant temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input related to heater matrix coolant temperature. The sensor is installed in the casing of the heater assembly and presses against the end tank of the heater matrix.

Ambient temperature sensor The ambient temperature sensor is an encapsulated thermistor that provides the ATC ECU with an input of external air temperature. The sensor is attached to the cooling fan mounting bracket in front of the condenser.