AC Compressor Clutch Diagnosis & Repair | MDH MOTORS An electromagnetic clutch provides the mechanical link between the pulley and the compressor input shaft whenever air conditioning is demanded. The compressor drive hub is usually found at the front of the pulley and is attached directly to the compressor driveshaft. Car AC compressor clutch — Ricks Free Auto Repair Advice Jan 27, 2017A car AC compressor clutch is used to connect and disconnect drive power to the car’s AC compressor shaft. Unlike a car’s transmission clutch, an AC compressor clutch is either transmitting full drive power to the AC compressor or not—it’s not supposed to provide partial power. How Do I Check an AC Clutch Relay? | It Still Runs The air conditioning clutch relay transfers power, like a switch, from the interior A/C controls of an automobile to the A/C compressor, engaging the compressor clutch. Checking an A/C clutch relay is a process of eliminating possible connection failures.