Why does the car air conditioner blow hot air instead of cold air?

[KaiFitz]

The main reason why a car air conditioner blows hot air instead of cold air is refrigerant leakage. The following are the related causes: 1. Refrigerant leakage: The symptoms include both the indoor and outdoor units working, the compressor operating, but with no cooling effect. 2. Damaged or faulty compressor capacitor: The symptoms include both the indoor and outdoor units working, but the compressor not operating, resulting in no cooling effect. 3. Four-way valve cross leakage: The four-way valve (this fault does not occur in single-cooling units) or compressor high and low pressure cross leakage, caused by improper relocation operations leading to severe refrigerant leakage. When there is severe refrigerant leakage and only a small amount of refrigerant remains in the pipeline, running in cooling mode will result in blowing hot air instead of cold air. It is recommended to conduct a leak detection on the entire air conditioning system pipeline, locate the refrigerant leakage point for repair, and after ensuring the vacuum pump achieves qualified negative pressure, refill with the standard amount of new refrigerant.