Why is the car air conditioning not cooling?
2 Answers
The car air conditioning not cooling may be due to refrigerant leakage, substandard refrigerant quality, or damaged/bad compressor capacitor. 1. Four-way valve gas leakage: Heat pump air conditioners use four-way valves to switch between cooling and heating modes. During cooling, the outdoor heat exchanger acts as a condenser while the indoor heat exchanger absorbs heat as an evaporator. In heating mode, their roles reverse. If the four-way valve leaks gas, some refrigerant that should participate in heat exchange directly returns from the compressor outlet pipe to the return pipe at the four-way valve, reducing heat exchange efficiency. External manifestations include unstable high/low pressure and uneven temperature in pipes connected to the four-way valve. Some faults may resemble insufficient refrigerant or inadequate cooling/heating, but high-side pressure remains normal during testing. 2. Defrost controller failure: For heat pump air conditioners in heating mode where the evaporator is in the outdoor unit, if the defrost controller malfunctions and fails to initiate timely defrosting, frost will accumulate on the evaporator, reducing heating efficiency or causing shutdown. Check for: misplaced defrost temperature sensors, stuck/bad contacts, slipping fan blades, blocked air ducts, or failed solenoids/start relays. 3. Auxiliary electric heating failure: Most heat pump air conditioners now use PTC auxiliary heating technology, which provides rapid, powerful and safe heating in extremely low temperatures. If the auxiliary heating circuit or device fails, it will cause insufficient heating capacity in low temperatures (below 0°C) while working normally in higher temperatures (above 5°C). These components should be prioritized during troubleshooting.
My car also had an issue with the A/C not cooling properly, and it turned out to be due to insufficient refrigerant. Turns out, when you use it a lot in the summer, low refrigerant levels can make it less effective. Also, I checked the A/C compressor—if that's broken, it won’t cool at all. Electrical issues shouldn’t be overlooked either, like blown fuses or loose wiring, which can prevent the A/C from turning on. Additionally, if the condenser is clogged with dust, poor heat dissipation can affect cooling performance. I’d suggest starting with the basics—check for signs of refrigerant leaks or inspect the air filter. If you can’t figure it out yourself, take it to a repair shop to test the system pressure. Remember to maintain your A/C regularly—don’t wait until there’s a problem to act. This can save you a lot of hassle.
