Air Conditioning Switch: Description and Operation

AIR CONDITIONING SWITCH SENSE-PCM INPUT
When the air conditioning or defrost switch is put in the ON position and the low pressure switch, combination valve, and high pressure switch close, the PCM receives an A/C input. After receiving this input, the PCM activates the A/C compressor clutch by grounding the A/C clutch relay. The PCM also adjusts idle speed to a scheduled RPM to compensate for increased engine load.