What is an evaporator temperature sensor?
An air conditioning evaporator temperature sensor—also known as an evap temperature switch, evaporator temp sensor, or evaporator core temperature sensor—monitors the temperature of the refrigerant in the AC evaporator core. The AC system uses the information from the sensor to regulate the cooling process and maintain a consistent cabin temperature.
When should I replace the evaporator temperature switch on my car?
Since there are no set replacement intervals for the evaporator temp sensor, you’ll only need to replace yours when it displays signs of failure. Here are the most common signs that you need a new sensor:
The AC system doesn’t blow cold air: One of the primary symptoms of a bad evaporator temp sensor is a lack of cold air from the AC system.
The AC temperatures fluctuate: Fluctuating AC temperatures are a common sign of a faulty evaporator temperature sensor. If the sensor sends incorrect signals to the computer, the AC system may behave erratically. The temperature may bounce between hot and cold, putting more stress on the system.
The AC compressor doesn’t turn on: The evap temperature sensor plays a key role in turning the compressor on and off. If the sensor fails, it may disable the compressor altogether.
Keep in mind: These symptoms may indicate other HVAC issues, like a faulty condenser or a bad cabin air filter. The best way to get an accurate diagnosis is to visit a professional mechanic.
How often should I replace my evaporator temperature sensor?
The evaporator temperature sensor is not a regular maintenance item. There are no set replacement intervals for the sensor, and you’ll only need to replace yours if it fails. Some of the most common signs of sensor failure include AC temperature fluctuations and a lack of cold air.
Can I replace my evaporator temperature switch myself?
An AC evaporator temperature sensor replacement is not the most accessible DIY project. It requires mid-to-advanced level automotive repair skills and knowledge of car HVAC systems. While experienced home mechanics should be able to handle the project, novices are better off contacting a professional.