Your car’s air conditioning system helps keep you and your passengers cool and comfortable during hot weather. It also plays a role in operating the front defroster. In order to operate properly, the system needs a refrigerant – just like your home air conditioning system, your refrigerator and other similar systems.
The refrigerant must be pumped through the A/C system in order to absorb heat. The compressor is responsible for pressurizing it, which transforms the gas into a liquid, and then it’s sent through the “high” side of the system. The right pressure level must be maintained at all times in order for your A/C to work properly. The refrigerant pressure sensor (switch) monitors the pressure in the system.
You’ll find the refrigerant pressure sensor (switch) mounted to one of the refrigerant lines near the back of the engine, close to the firewall. It keeps tabs on the pressure in the system and if there is a serious drop in pressure, it shuts the entire thing down (insufficient pressure could damage air conditioning components). If the sensor/switch fails, the system will also be shut down.
Without an operational air conditioner, driving during high summertime temperatures or in year-round warm climates would be uncomfortable at best and dangerous at worst. Keep an eye out for the following signs that your car’s refrigerant pressure sensor (switch) is failing:
The air conditioner takes a long time to produce cool air (this can also be a sign of low refrigerant)
The air conditioner doesn’t blow cold air at all
You hear a whistling sound from under the hood, near the back of the engine
If you suspect that your refrigerant pressure sensor (switch) is failing, or you’re experiencing any other problem with your car’s air conditioner system, turn to a certified mechanic. A professional will be able to inspect the A/C system and repair or replace the pressure sensor/switch, and anything else that is damaged.