Is Your Evaporator Temperature Sensor Failing? Find Out

The evaporator temperature sensor is a switch that detects and monitors the temperature of the evaporator. The sensor acts as a safety feature by maintaining the evaporator temperature between certain limits to prevent freezing or overheating. However, if the switch malfunctions, it will not accurately detect the temperatures hence tripping the circuit breaker that shuts the system off. Therefore, it is imperative to hire an AC appliance repair specialist to diagnose your unit and repair the switch for peak functionality. Below are the signs your evaporator temperature sensor is defective.

No Cold Air From The Vents

A faulty evaporator temperature switch will transmit incorrect signals to the AC as it inaccurately detects temperatures. For instance, if it detects the temperature as cooler than that set on the thermostat, it will not run any cooling cycles; hence you will have no cold air from the vents. Alternatively, if you have the fan setting on, you will experience lukewarm air from vents as the fan continues to blow the air even when it is not cycling. Thus, it is wise you contact an AC professional to install a new sensor for accurate detection of indoor temperatures for cooling to occur.

AC Unit Runs Constantly

When the evaporator temperature sensor fails, it will not turn off after attaining the thermostat setting. This is because the sensor detects the temperature warmer than the actual one, resulting in the AC running non-stop until the temperatures significantly drop. Consequently, you will experience extremely cold drafts in your home. This exerts strain on the AC components due to constant operation, making them wear much faster. Since the unit running constantly leads to rising energy bills, you must engage an AC appliance repair service contractor to replace the sensor for seamless and effective operation.


When the evaporator temperature sensor displaces from the original position, it will erratically measure the air temperature. This results in the AC working intermittently hence cycling on and off randomly before attaining the programmed temperatures. Moreover, frequent short cycling will hasten the wear and tear of the AC, making it prone to breakdowns. Finally, a failing temperature switch will cause non-uniform temperatures in your home as the areas close to vents will be cooler than others as they receive conditioned air faster before the unit short cycles. Since the cooling system will consume more energy in the repetitive start-up phases, you should call an AC expert to install a new sensor.

A faulty temperature sensor will cause secondary damage to other components resulting in a system breakdown. Thus, you should employ the services of an AC appliance repair service specialist to regularly tune up your system for accurate temperature detection and peak efficiency.

For more information on appliance repair, contact a professional near you.