Why does the car air conditioner not cool when running but cools when parked?

[DiReed]

If the car air conditioner does not cool when running but cools when parked, the reasons are as follows: 1. Lack of Freon: The lower engine speed causes the compressor speed to be relatively lower, and the lack of Freon means the instantaneous pressure boost does not reach the standard state, resulting in low high pressure and suboptimal cooling performance. 2. Compressor pressure leakage: This directly leads to severely low pressure during idle. 3. Air conditioner cooling fan not working: When parked, due to insufficient cooling and the absence of wind speed during driving to lower the temperature, the pressure becomes excessively high, causing the high-pressure sensor to force the compressor to stop working, thus resulting in no cool air.