GM Service Manual Online
For 1990-2009 cars only

The A/C compressor control module controls the operation of the compressor clutch in response to signals received from the following:

    • The A/C ON/OFF switch
    • The A/C refrigerant pressure switch
    • The Powertrain Control Module (PCM)

With the air conditioning system in operation, the A/C compressor control module performs the following functions:

    • Energizes the compressor clutch in response to the following:
       - An A/C system ON request
       - The determination of favorable system conditions for air conditioning operation.
    • De-energizes the compressor clutch in response to the following:
       - An A/C system OFF request
       - A high refrigerant pressure signal (from the A/C refrigerant pressure switch)
       - A low refrigerant pressure signal (from the A/C refrigerant pressure switch)
       - A high engine demand signal (from the PCM).