A/C Clutch

When PCM detects a signal from the air conditioner PCM indicating that the A/C switch is turned on, PCM will output a signal to the magnetic clutch relay to turn it on.

The magnetic clutch operation is delayed for about 0.5 second. During this time, the PCM opens the ISC valve to offset the drop in engine RPM due to the operation of the A/C compressor.

This system also helps maintain driveability by switching off magnetic compressor clutch when vehicle is accelerated suddenly, or when engine is running under a heavy load condition.