Why is one side of the Mercedes-Benz air conditioning cold while the other is not?

[OEmiliano]

Mercedes-Benz air conditioning being cold on one side but not the other may be due to settings. High-configuration Mercedes-Benz models feature dual-zone climate control, requiring separate temperature and airflow settings for both the driver and passenger sides. If the settings are correct, the issue could stem from insufficient refrigerant, a damaged air conditioning flap, a dirty condenser, or malfunctions in the compressor, throttle valve, or expansion valve, as well as belt aging. Below are detailed explanations of these potential causes: 1. Insufficient Refrigerant: Car air conditioning systems typically require refrigerant replenishment every 2-3 years. Refrigerant loss is often due to leaks. If the air conditioning performance deteriorates shortly after a refrigerant refill, this should be noted. 2. Damaged Air Conditioning Flap: While rare, flap motor failure can occur. If no air flows from any vents after turning on the air conditioning, replacing the flap motor may require dashboard removal. 3. Dirty Condenser: During summer, poor air conditioning performance may result from a dirty condenser, even if the system tests normal. Many repair shops recommend cleaning the radiator and condenser to improve heat dissipation. Accumulated debris, such as spring pollen, can obstruct the condenser, leading to engine overheating or poor air conditioning. 4. Compressor, Throttle Valve, or Expansion Valve Malfunction: Compressor failure is uncommon, but issues with the throttle or expansion valve can directly impair air conditioning performance. Diagnosing these requires professional expertise. 5. Worn or Loose Belt: Maintenance typically includes belt replacement reminders. Neglecting this can cause belt slippage, leading to breakage, noise, power steering failure, or air conditioning issues.