Refrigerant Pressure Sensor / Switch: Description and Operation
A/C PRESSURE TRANSDUCERThe A/C pressure transducer is located on the discharge line near the compressor, and functions as the refrigerant system pressure sensor. This switch prevents compressor operation when the discharge line pressure approaches extreme levels.
The A/C pressure transducer is a factory-calibrated unit. The switch cannot be adjusted or repaired, and if faulty or damaged, it must be replaced.
When the discharge line pressure rises above 2971 kPa (431 psi) the switch contacts open and interrupt the A/C clutch relay signal from the PCM. The switch also opens when the pressure drops below 206 kPa (30 psi). The PCM responds by de-energizing the compressor clutch relay, which will disengage the compressor clutch.