Control Module HVAC: Description and Operation

The A/C amplifier controls the operation of the compressor clutch in response to signals received from the A/C dual pressure switch, the evaporator temperature sensor, and the Powertrain Control Module (PCM).

With the air conditioning system in operation, the A/C amplifier performs the following functions:

^ Energizes the compressor clutch in response to air conditioning system request and upon determination of favorable system conditions for air conditioning operation.
^ De-energizes the compressor clutch in response to a high refrigerant pressure signal (from the dual pressure switch), a low refrigerant pressure signal (from the A/C dual pressure switch), a low evaporator temperature signal (from the evaporator temperature sensor), or a high engine demand signal (from the PCM).