What Causes the Rear Air Conditioning in BMW 3 Series to Not Cool?

[DelJoshua]

If the air conditioning is not cooling, first check if there is a lack of refrigerant. 1. Refrigerant Leakage: High-pressure liquid refrigerant enters the dryer reservoir through the pipeline. After drying and filtering, it flows into the expansion valve for throttling, where its state changes drastically, turning into low-temperature, low-pressure liquid refrigerant that enters the evaporator. In the evaporator, it absorbs heat from the air passing through, lowering the air temperature and producing cold air for cooling. Without sufficient refrigerant, the air conditioning cannot function. 2. Compressor Damage: If the airtightness of the compressor cylinder is compromised, such as when there is gas leakage between the high and low-pressure chambers, the cooling or heating efficiency of the air conditioning will be significantly reduced, though not completely ineffective. In such cases, testing the working pressure and current of the air conditioning will show values outside the normal range.