Evaporator Temperature Sensor / Switch: Description and Operation

Fig.15 Evaporator Temperature Sensor:

The evaporator temperature sensor is located at the coldest point on the face of the evaporator. The switch is attached to the evaporator coil with the sensing probe inserted into the coil fins. The evaporator temperature sensor prevents condensate water on the evaporator coil from freezing and obstructing A/C system air flow.

The sensor is used to switch the clutch OFF before evaporator freeze-up occurs. Output from the probe is sampled by the Body Control Module. The clutch is switched OFF when the sensor temperature reaches 1.1 °C (34 °F). The clutch is switched back ON when the sensor temperature reaches 2.2 °C (36 °F).