Refrigerant Pressure Sensor / Switch: Description and Operation

A/C PRESSURE SWITCHES

The A/C system is protected by two A/C pressure switches. The A/C high pressure switch interrupts the A/C request signal when the A/C line pressure exceeds 2965 kPa (430 psi). When high side pressures drop down to 1379 kPa (200 psi), the A/C high pressure switch will close and allow compressor operation. The A/C low pressure switch interrupts the A/C low pressure switch signal when the A/C line pressure drops below 69 kPa (10 psi). When the PCM stops receiving the required signals, the A/C compressor clutch relay control circuit is no longer grounded, thus shutting off the compressor.