Refrigerant Pressure Sensor / Switch: Description and Operation

SYSTEM OPERATION
A/C Pressure Transducer

A/C Pressure Transducer:

The A/C Pressure Transducer monitors the refrigerant gas pressure on the high side of the system. The transducer is located 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.

AIR CONDITIONING PRESSURE TRANSDUCER-PCM INPUT
The Powertrain Control Module (PCM) monitors the A/C compressor discharge (high side) pressure through the air conditioning pressure transducer. The transducer supplies an input to the PCM. The PCM engages the A/C compressor clutch if pressure is sufficient for A/C system operation.