2012 Toyota Avalon - Radiator Fan Relay

Air Conditioning Clutch Cycling Switches

The A/C clutch cycling switch, also known as a cycling switch or A/C pressure switch, measures system pressure to detect the flow of refrigerant in the A/C system. This sensor can be located in several different places depending on the vehicle's A/C system design. When the pressure has dropped to a certain level, this switch deactivates the clutch to prevent it from engaging and stopping the operation of the A/C compressor to avoid potential damage. If the compressor runs for any period of time without sufficient refrigerant levels or low refrigerant oil, the lack of lubrication can cause compressor damage and eventual failure. Once the pressure is restored during an A/C system recharge, the switch will then allow the clutch to engage and the compressor to operate. Like most electrical components, an A/C clutch cycling switch may need to be replaced due to its internal contacts wearing out and no longer maintaining a connection with the A/C clutch. In some cases, the A/C cycling switch may also allow power to flow to the clutch even when refrigerant levels are low, which could cause extensive A/C compressor damage. Signs that your A/C clutch cycling switch may be failing include a lack or total loss of cooling from your A/C system due to its inability to activate the compressor, or your compressor may run constantly without cycling. These issues could also be related to a failing A/C relay or clutch, so be sure to perform a complete diagnosis before beginning your repair. O'Reilly Auto Parts carries a selection of new A/C clutch cycling switches, refrigerant, A/C compressors, and refrigerant oil for a complete repair.