A/C Low Pressure Switch

The low pressure switch is located in the low pressure refrigerant line. When pressurized, the switch is closed and allows the compressor clutch relay to energize. This feeds the battery voltage to the compressor clutch coil. If the pressure drops below 69 kPa (10 psi), the switch opens and cuts off the voltage to the clutch. A circuit to the heater and A/C programmer monitors the state of the switch for diagnostic purposes.