Refrigerant Pressure Sensor / Switch: Description and Operation

The pressure switch of the Air Conditioning (A/C) refrigerant is located along the right front inner fender. The A/C refrigerant pressure switch is in the liquid pipe between the receiver-dryer and the evaporator. The A/C refrigerant pressure switch acts in order to cycle the compressor on and off under the following conditions:
^ Abnormally low refrigerant pressure
^ Abnormally high refrigerant pressure

If the pressure drops below 193 kPa (28 psi) or rises above 3137 kPa (455 psi), the A/C refrigerant pressure switch opens. The A/C refrigerant pressure switch signals the A/C compressor control module to shut down the compressor.

An insufficient refrigerant supply or a very low refrigerant temperature can cause an abnormally low refrigerant pressure. The following conditions can cause an abnormally high refrigerant pressure:
^ Very high refrigerant temperatures
^ Over charging the system during service.