Your Mercedes vehicle will flash a host of service lights 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 unit isn’t actually damaged, and resetting your climate control unit will allow your air conditioner to work as it did before. Be aware that if you reset the unit and it again stops working, you need to take the vehicle in to the dealership for repairs.
Insert the key into the Mercedes ignition and turn the ignition cylinder to the “2” position. This is as far as the cylinder will go without cranking the engine.