What are the reasons for the Corolla's air conditioning not cooling?

[McXavier]

Analysis of the reasons for the Corolla's air conditioning not cooling is as follows: 1. Excessive dirt: Too much dirt in the refrigerant and refrigeration oil of the air conditioning system can clog the filter screen, increasing resistance and reducing the flow of refrigerant to the expansion valve, leading to the air conditioning not cooling. 2. Insufficient refrigerant: Since refrigerant can evaporate, air conditioning systems used for three to four years may require a refrigerant refill. Insufficient refrigerant can also be observed through the sight glass on the top of the dryer. During normal operation, if continuous slow bubbles are seen in the sight glass, it indicates insufficient refrigerant. 3. Reduced condenser heat dissipation capacity: A decrease in the condenser's heat dissipation ability can also lead to a reduction in the air conditioning's cooling performance.