Compressor Clutch: Description and Operation

Air Conditioning Pressure Switch Schematic:

Air Conditioning Cycle Switch
The Air Conditioning Cycle Switch (ACCS) indicates to the Powertrain Control Module (PCM) when the A/C demand switch is turned ON. Both the cyclic pressure switch and high pressure contacts of the dual function A/C Pressure Switch (ACPSW) are closed, voltage is supplied to the ACCS circuit signal at the PCM.

Air Conditioning Pressure Switch
The dual function A/C Pressure Switch (ACPSW) is referred as the refrigerant containment/fan function switch. The normally open medium pressure contacts close at a predetermined A/C head pressure.
The normally closed high pressure contacts open at a predetermined A/C head pressure. This turns OFF the A/C by opening the A/C demand circuit, preventing A/C pressure from rising to a level that would OPEN the A/C high pressure relief valve.