A/C Compressor Clutch - Operation

A/C CLUTCH

The A/C compressor clutch components provide the means to engage and disengage the A/C compressor from the engine accessory drive belt. When the electromagnetic A/C clutch coil is energized, it magnetically draws the clutch plate into contact with the clutch pulley and drives the compressor shaft. When the A/C clutch coil is not energized, the pulley freewheels on the clutch hub bearing, which is part of the pulley assembly.

A/C clutch engagement is controlled by the Powertrain Control Module (PCM) or Engine Control Module (ECM), depending on engine application. When the A/C-heater control is set to any A/C position, it sends a request signal on the CAN-B bus to the Totally Integrated Power Module (TIPM), which then transfers the request on the CAN-C Bus to the PCM/ECM, which determines if operating conditions are correct for A/C clutch engagement. When all operating conditions have been met, the PCM/ECM sends a signal on a dedicated hard-wired circuit back to the TIPM to energize the internal A/C clutch high side driver. When energized, the A/C clutch high side driver provides battery current to the A/C clutch coil.

The A/C clutch control system is diagnosed using a scan tool Testing and Inspection or (Refer to Engine Control (ECM) - Diagnosis and Testing).

The A/C clutch components cannot be repaired and must be replaced if inoperative or damaged.