Low Refrigerant Pressure Switch
WARNING: This page is about a different car, the 1995 Cadillac Seville, 1995 Cadillac Eldorado, and 1995 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
The low refrigerant pressure switch is located in the low-pressure refrigerant line. When pressurized, the switch is closed and allows the ignition circuit to feed the compressor clutch coil through the compressor clutch relay. If refrigerant pressure drops to less than approximately 10 psi (0.7 kg/cm2 ), the switch opens the circuit to the clutch. The ACP monitors the switch for diagnostic purposes.