Compressor Clutch Relay: Description and Operation

The A/C clutch control relay supplies voltage to the A/C compressor and is controlled by the Powertrain Control Module (PCM). The PCM reads the input voltage from the A/C pressure cut-off switch and sends voltage to the A/C clutch control relay accordingly. When the electrical contacts of the A/C pressure cut-off switch are closed, the PCM sends voltage to the A/C clutch control relay, which in turn energizes the A/C compressor clutch to engage the A/C compressor.