A/C Clutch

An electromagnetic clutch is energized when the clutch cycling pressure switch closes. The switch is located on the suction accumulator/drier. The closing of the switch completes the circuit to the clutch and draws it into engagement with the compressor driveshaft. When the A/C is engaged, EPC  pressure is adjusted to compensate for the additional load on the engine if the Electronic Throttle Control (ETC) signal is not available.