Operation CHARM: Car repair manuals for everyone.

A/C Pressure Switches

The A/C system is protected by two pressure switches. The A/C high pressure switch interrupts the A/C request signal when the A/C line pressure exceeds a predetermined value. The A/C low pressure switch interrupts the A/C low pressure switch signal when the A/C line pressure drops below a predetermined value. When the PCM stops receiving the required signals, the A/C compressor clutch relay control circuit is no longer grounded, thus shutting off the compressor.