Refrigerant Pressure Sensor / Switch: Description and Operation

The Electronic Cycling Clutch Switch (ECCS) is located on the A/C refrigerant line at the expansion valve. The ECCS prevents evaporator freeze-up by signaling the Engine Controller Computer to cycle the compressor ON and OFF by monitoring the temperature of the suction line.

The ECCS uses a thermistor probe in a capillary tube. This is inserted into a capillary tube well on the suction line. The well must be filled with conductive grease to prevent corrosion and allow thermal transfer to the probe. The ECCS is a sealed unit and cannot be adjusted or repaired. It must be replaced if found defective.