Refrigerant Pressure Sensor / Switch: Description and Operation
A/C PRESSURE TRANSDUCERThe A/C pressure transducer is an electromechanical device that functions as the refrigerant system pressure sensor. The PCM uses information from the transducer to control the radiator fans and compressor functions. The sensor is attached to a threaded valve on the liquid line.
The pressure transducer turns OFF the voltage to the compressor clutch coil when refrigerant gas pressure drops to levels that could damage the compressor. The transducer also is used to adjust condenser fan speeds and will turn off compressor at high refrigerant pressures. The pressure transducer is a sealed factory calibrated unit. It must be replaced if defective. O-ring replacement is required whenever the pressure transducer is serviced. Be sure to use the O-ring specified for the transducer.