A/C Pressure Switch

The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator/drier.
^ A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.
^ This allows the suction pressure inside the suction accumulator/drier to control the operation of the A/C cycling switch.
^ The electrical switch contacts open when the suction pressure drops to 152-193 kPa (22-28 psi).
^ The contacts close when the suction pressure rises to 276-324 kPa (40-47 psi).
^ When the A/C cycling switch contacts close, the signal to energize the A/C clutch is sent to the Powertrain Control Module (PCM).
^ When the A/C cycling switch contacts open, the A/C clutch field coil is deenergized and compressor operation stops.
^ The A/C cycling switch will control the A/C evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing.
^ This prevents icing of the A/C evaporator core and blockage of airflow.
^ It is not necessary to discharge and recover the refrigerant system to remove the A/C cycling switch.