The refrigerant pressure sensor, or switch, is designed to protect the A/C system against incorrect refrigerant pressure. There are low-pressure cutout sensors and high-pressure cutout sensors. The low-pressure cutout sensor can be found on either the high or low side of the system and is used to disengage the compressor clutch if pressure gets too low.
On the other hand, the high-pressure cutout sensor is typically located on the high side of the A/C system and is used to disengage the compressor if pressure gets too high. The most common symptom of a failed refrigerant pressure sensor is A/C that doesn’t work or works intermittently, but you may also notice that it blowers warm air.
Part of 1 of 1: Replacing the refrigerant pressure sensor
- Repair manuals
- Protective gloves
- Safety glasses
- Wrench of the appropriate size
Step 1: Locate the refrigerant pressure sensor. The refrigerant pressure sensor is typically mounted to the A/C pressure line, compressor, or accumulator/drier.
Step 2: Disconnect the negative battery cable. Disconnect the negative battery cable with a wrench of ratchet and set it aside.
Step 3: Remove the sensor electrical connector.
Step 4: Remove the sensor. Use a wrench to loosen the sensor, and then unscrew it.
- Note: In most cases there is a schrader valve built into the sensor mount. Because of this, the A/C system does not need to be evacuated prior to sensor removal. However, it’s a good idea to consult the factory repair information for your vehicle before removing the switch.
Step 5: Install the new sensor. Screw in the new sensor in by hand, and then tighten it down using a wrench.
Step 6: Reinstall the electrical connector.
Step 7: Reinstall the negative battery cable. Reinstall the negative battery cable and tighten it.
You should now have a working AC system to keep you comfortable on the road. If this sounds like a job you’d rather leave to a professional or if you don’t feel confident completing the repair yourself, have one of YourMechanic’s certified technicians perform a refrigerant pressure sensor replacement.
This article originally appeared on YourMechanic.com as How to Replace a Refrigerant Pressure Sensor and was authored by Mia Bevacqua.