Why is one side of the car air conditioner cold and the other side hot?
2 Answers
Here are the reasons why one side of the car air conditioner is cold and the other side is hot: 1. Temperature settings are different on each side: Dual-zone air conditioning requires adjusting the temperature for both the driver's and passenger's sides. If one side is set lower, it may result in one side being hot and the other cold. 2. The hot/cold knob is not adjusted correctly: For example, hot air is blowing but the knob is not turned to the red setting, or cold air is blowing but the knob is not turned to the blue setting. 3. Insufficient refrigerant: Or there may be too much refrigerant. 4. Clogged heater valve: Automatic dual-zone air conditioning uses two water pipes to the heater core. If one is clogged and the other is not, the temperature will differ on each side, and the air output temperature will also vary. It is recommended to replace the water pipes. 5. Damaged stepper motor: Replacement is recommended. 6. Air conditioning computer malfunction: This can cause the control of the hot/cold pipe valve to fail. Try resetting the computer.
In all my years of car repair, I've encountered this uneven cooling issue quite often. The most common cause is a malfunctioning air blend door actuator. Think about it - that blend door in the AC duct controls the mix ratio of hot and cold air. If it gets stuck or fails, the airflow distribution between left and right becomes uneven. Some older vehicles may experience clogged heater control valves, disrupting the hot water circulation on one side. Also remember to check the AC refrigerant pressure - insufficient refrigerant or leaks can also cause uneven cooling performance. Finally, I recommend setting all temperature controls to maximum cold when testing. If you still get hot air on one side and cold on the other, it's most likely a mechanical failure.
