Air conditioning (Heater assembly): Description and operation

Heater assembly

1 Distribution servo motor 2 Refrigerant inlet and outlet connector block 3 RH blend flap servo motor 4 Thermostatic expansion valve 5 LH blend flap servo motor

The heater assembly controls the temperature and distribution of air supplied to the distribution ducts, and is similar to the heater assembly installed in non A/C vehicles. HEATING AND VENTILATION, DESCRIPTION AND OPERATION, Description. The only differences from the heater assembly in non A/C vehicles are as follows: l The thermostatic expansion valve, evaporator and evaporator temperature sensor are installed at the air inlet side of the casing. l Three servo motors operate the control flaps instead of control cables. l A coolant temperature sensor is installed against the heater matrix.

The servo motors are controlled by the ATC ECU. Feedback potentiometers in the servo motors provide the ATC ECU with flap position signals.