What is the AC High Pressure Switch all about?
This switch is a safety device. If the pressure in the air conditioning system becomes too high, it switches off the compressor so that hoses, seals and the compressor are not damaged. On many cars it also helps control the radiator cooling fan.
Keep in mind:
High pressure is usually a symptom, not the cause. A dirty or blocked condenser, an overfilled system or a failed cooling fan can all cause it. Dust and plastic bags can clog a condenser quickly, which makes this common on dusty roads. The system should only be opened by a trained technician with recovery equipment.
How it's done:
- System pressures are read and the condenser and cooling fan are checked.
- The switch and wiring are tested.
- The refrigerant is recovered, the switch is replaced and the system is recharged.
- The system is leak tested and cooling performance is checked.
Our recommendation:
Have the condenser cleaned at each service and do not top up refrigerant yourself. An overfilled system can damage the compressor.
What common symptoms indicate you may need to replace the AC High Pressure Switch?
- The air conditioning switches off suddenly, especially in traffic or on hot days.
- The compressor does not engage at all.
- The cooling fan runs constantly or not at all.
- Air is warm while the engine is hot.
How important is this service?
Important. A switch that fails to protect the system can lead to burst hoses or a ruined compressor.