HVAC Systems - Automatic

The A/C system is protected by two pressure switches. The A/C high pressure switch interrupts the A/C request signal circuit when the A/C line pressures climb above 2826 kPa (410 psi). The A/C low pressure switch interrupts the A/C low pressure switch signal circuit when the A/C line pressures fall below 207 kPa (30 psi). When the PCM sees an open in either signal, the A/C clutch relay control circuit is no longer grounded, thus shutting off the compressor. When high side pressures drop back down between 1034 kPa (150 psi) to 1724 kPa (250 psi), the PCM will allow the A/C compressor to operate.