What is the AC Pressure Switch all about?

Your car’s air conditioning system uses a refrigerant that takes on different characteristics at different pressures. Under low pressure, the refrigerant is a gas. Under high pressure, it’s a liquid. This means there are technically two “sides” to the AC system – the high pressure side and the low pressure side. Both sides must monitor pressure to ensure safe operation. One of the safety features built into modern air conditioning systems is a pressure switch – the AC low pressure switch is designed to trip if there’s a pressure-related issue on the low side, and the high pressure switch on the high side.

The AC pressure switch basically turns a side of the system off if certain events take place. There are numerous causes of low or high pressure switch tripping, and not all of them involve switch failure. A low refrigerant charge can cause the low pressure switch to read incorrectly. The same goes for a high refrigerant charge.

Keep in mind:

• AC pressure switch operation is generally not checked unless there is a problem.
• Many different problems can cause symptoms consistent with pressure switch failure.

How it's done:

• The AC pressure switch is verified to see if it needs to be replaced
• The defective AC pressure switch is removed
• The new AC pressure switch is installed
• The AC pressure switch is tested for operation
• The AC is tested to ensure proper operation of the AC pressure switch

Our recommendation:

We recommend having your car’s AC system professionally inspected and maintained at all times. Ongoing, regular maintenance is the best way to ensure that all components are in good working condition, and to hone in on the actual problem causing symptoms. If you suspect your AC pressure switch is faulty or there is something else wrong with the air conditioning, have one of our expert mechanics diagnose and repair it.

What common symptoms indicate you may need to replace the AC Pressure Switch?

• AC does not operate
• AC compressor will not turn on

How important is this service?

Your car’s air conditioning system isn’t vital for overall vehicle operation. However, it’s an important convenience and comfort feature, particularly in areas with high summertime temperatures or humid conditions. If your AC isn’t working properly, have it diagnosed by one of our expert mechanics.