Evaporator Temperature Sensor / Switch: Description and Operation

EVAPORATOR FIN SENSOR
The evaporator fin sensor is located in the heater A/C housing and placed in the evaporator fins. The evaporator fin sensor can be replaced without having to remove the heater-A/C housing from the vehicle.

The sensor prevents evaporator freeze-up. This is done by cycling the compressor clutch OFF when evaporator temperature drops below freezing point. It cycles ON when the evaporator temperature rises above freezing point. The evaporator fin sensor uses a thermistor probe in a capillary tube. The tube is inserted between the evaporator fins in the heater- A/C unit housing.