1. Before checking the temperature of the high and low pressure pipes, the air conditioner should be set to the position of maximum cooling, maximum air volume, direct blowing, air circulation, and A/C switch on. The temperature of the air outlet, according to experience, is around 5 degrees Celsius, which is normal.

2. Raise the engine hood to confirm that the electronic fan is running simultaneously and the compressor is also running. If it is not running, loosen the protective cover of the high-pressure pipe and use a sharp tool to gently press the high-pressure exhaust pin to see if there is a strong refrigerant overflow. If there is, it indicates that the fault of the air conditioning is in the circuit system. If there is no strong leakage of refrigerant, please carefully check whether there are oil stains on the joints of the air conditioning pipes. If there are any, it indicates that there is a leakage point in the air conditioning system. This repair may be time-consuming, and it is also possible that one area has been repaired, and there may be other leaks, which is inevitable. Please have the car owner fully understand the repair of the leak. Finally, remember to tighten the protective cover.

3. Touch the high-pressure and low-pressure pipes with your hands and carefully feel their temperature. When the refrigeration system is working normally, the normal temperature of the high-pressure pipe is about 50 to 60 degrees Celsius, which means that it can be firmly held by hand for about 30 seconds. No matter how long it takes, it cannot be held. The temperature of the low-pressure pipe is approximately between 5 and 6 degrees Celsius, which means you can feel it with your hands.