A/C Cycling Switch Description

Fig 1: Identifying A/C Cycling Switch

Courtesy of MAZDA MOTORS CORP.

The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the receiver/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 receiver/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 A/C clutch relay.
• When the A/C cycling switch contacts open, the A/C clutch field coil is de-energized and compressor operation stops.
• The A/C cycling switch will control the evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing.
• This prevents icing of the evaporator core and blockage of airflow.
• It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.