Compressor Control

The Compressor for the Air Conditioning System is driven by the engine by means of a belt drive and the A/C Compressor Clutch. The Clutch allows the Compressor to be disengaged when Air Conditioning is not required.

When the Ignition Switch is in RUN, battery voltage is supplied to the Heater and A/C Control Module through CKT 141 and the A/C Compressor Clutch Relay by means of CKT 1240, Low Pressure Cutout Switch, and CKT 603. With A/C "ON" requested, the Heater and A/C Control Module supplies voltage to coil of the A/C Compressor Clutch Relay and grounds through CKT 150. The relay switch closes sending power through CKT 203, the A/C High Pressure Cutout Switch, and CKT 59 to the A/C Compressor Clutch. The coil is then energized by grounding through CKT 150 and engages the clutch.

The A/C Compressor Clutch Diode is connected across the terminals of the A/C Compressor Clutch. Whenever the clutch is de-energized, the magnetic field around it collapses, generating and induced voltage in the clutch coil. The Diode provides a path for the current resulting from the induced voltage so that other circuit components are not damaged.