A/C Clutch Relay Operation

Theory of Operation:
The A/C compressor clutch relay controls the 12 volt source for the A/C clutch. The relay is located in the power distribution center. One side of the relay control coil is supplied with 12 volts when the ignition switch is turned to the run position. The circuit is completed when the other side of the relay coil is grounded by the powertrain control module (PCM). When A/C is requested, the PCM adjusts the idle speed to accommodate the A/C compressor load on the engine. The PCM grounds the relay control circuit after the PCM receives an A/C request and adjustment of the idle speed has been implemented.