Air Conditioning (A/C) Pressure Switch

Fig 1: Identifying Air Conditioning (A/C) Pressure Switch

Courtesy of VOLVO CARS CORPORATION

The air conditioning (A/C) pressure sensor detects the pressure in the low pressure side of the air conditioning (A/C) system. See also: REGULATING THE AIR CONDITIONING (A/C) COMPRESSOR 

The air conditioning (A/C) pressure sensor has a pressure sensing switch which is supplied powered by the fuse and grounded (signal) in the engine control module (ECM). The air conditioning (A/C) pressure sensor is affected by the pressure in the low-pressure pipe of the air conditioning (A/C) system (thick pipe).

The engine control module (ECM) cannot diagnose the air conditioning (A/C) pressure sensor.