Refrigerant Pressure Sensor / Switch: Description and Operation

An electronic A/C pressure transducer is mounted on the discharge line (high side) of the A/C compressor hose assembly. Its output to the PCM is variable and is dependent upon pressure inside the line. A higher pressure results in a higher voltage output. A/C pressure is constantly monitored to:

^ Disengage the A/C clutch if the pressures are high-2700 kPa (430 psi).
^ Disengage the A/C clutch if pressures are too low-below 303 kPa (35 psi).
^ Control cooling fan operation of low and high speed.