A/C Low Pressure Switch

The A/C low pressure switch is a single pole, single throw, pressure actuated switch that is installed in a threaded port into the suction passage of the accumulator on 2.0L LHD models or in a threaded port into the suction passage of the expansion valve on 2.4L and RHD models. The accumulator fitting on 2.0L LHD models contain a Schrader type valve, which allows the switch to be serviced without discharging the refrigerant system and is equipped with a O-ring to seal the switch plumbing connection. The A/C low pressure switch on 2.4L and RHD models can only be serviced with the refrigerant system discharged.

The A/C low pressure switch is factory calibrated and cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The A/C low pressure switch is electrically connected in series with the A/C-heater control mode switch and the A/C high pressure switch, between ground and the powertrain control module (PCM). The A/C low pressure switch contact opens or closes the path the ground, signaling the PCM to turn the A/C compressor clutch on and off. This regulates the refrigerant system pressure and controls evaporator coil temperature. Controlling the evaporator temperature prevents condensate water on the evaporator fins from freezing and obstructing air conditioning system air flow.

On 2.0L LHD models, the A/C low pressure switch contacts are open when the suction pressure is approximately 152 kPa (22 psi) or lower. The switch contacts will close when the suction pressure rises to approximately 234 to 262 kPa (34 to 38 psi) or above. Lower ambient temperatures, below approximately -1°C (30°F), will also cause the A/C low pressure switch contacts to open. This is due to the pressure/ temperature relationship of the refrigerant in the system.

On 2.4L and RHD models, the A/C low pressure switch contacts are open when the suction pressure is approximately 96 kPa (14 psi) or lower. The switch contacts will close when the suction pressure rises to approximately 234 to 262 kPa (34 to 38 psi) or above.