How to Reset a Mercedes AC System

Although they’re are a big name in luxury cars, many people report issues with the Mercedes air conditioning system. Issues with the AC unit can be caused by a number of issues, but the more common ones include: AC compressor issues, a refrigerant leak, a bad cooling fan unit, a worn-out evaporator, a slow blower motor, condenser leakage or electrical issues like a shoddy actuator.

Mercedes cars will flash a host of service lights on the control panel to inform you when something might be damaged inside the car. If the air conditioner unit is not running normally or is only blowing out warm air, it may be a temporary fault. Sometimes the air conditioning system isn’t actually damaged, and resetting your climate control unit will allow your air conditioner to work normally. Be aware that if you do an AC reset and the cool air stops working again later, you need to take the vehicle into the dealership for repairs. Here’s how to do a Mercedes climate control reset.

Turn the ignition key to the 2 position. This is as far as the ignition cylinder will go without cranking the engine and starting the AC system.

Press and hold the defrost and recirculated air buttons simultaneously to reset the climate control system. The defrost button has three lines going through it, while the recirculated air button has a picture of a car with a curved line through it. Hold these buttons down for about 10 seconds, or until the LED lights on both buttons start flashing.

Wait 45 to 60 seconds for the LED lights to stop flashing. Then turn off the car.

Wait 60 seconds and then start the car engine again.

Check to see if cold air is blowing out of the unit. If it is, you’ve succeeded in resetting your Mercedes’ AC system. If hot air is still blowing out, take the car to a professional.

If the problem seems fixed for a few days but then resumes later, take the vehicle to a Mercedes-Benz dealership. A certified technician will inspect the vehicle and find a solution to the issue.