Description And Operation: Operation
The rear A/C expansion valve controls the flow of high pressure, high temperature liquid refrigerant entering the expansion valve and converts it into a low pressure, low temperature mixture of liquid and gas before it enters the rear A/C evaporator. To meet the vehicles A/C cooling requirements, a mechanical sensor is used in the rear A/C expansion valve to monitor the temperature and pressure of the refrigerant leaving the rear A/C evaporator and then adjust the inlet port orifice size to allow only the proper amount of refrigerant to enter the evaporator. Controlling the refrigerant flow through the rear A/C evaporator ensures that none of the refrigerant leaving the evaporator is still in a liquid state, which could damage the A/C compressor.
Replacement of the refrigerant line O-ring seals and gaskets is required anytime a refrigerant line or expansion valve is disconnected. Failure to replace the rubber O-ring seals and metal gaskets may result in a refrigerant system leak.
The rear A/C expansion valve is factory calibrated and cannot be adjusted or repaired and must be replaced if inoperative or damaged. Refer to VALVE, A/C EXPANSION, DIAGNOSIS AND TESTING .