Mercedes-Benz W203 climate control flaps and temperature control
Mercedes-Benz W203: why does the air not adjust and the airflow go only to the feet or windscreen?
The most common cause is the plastic lever of the flap motor, which has cracked or broken. The unit interprets the flap as stuck when it does not move. Replacing the lever requires removing the centre console, radio and air vents, and takes about 2–3 hours at a workshop.
Mercedes-Benz W203: why does the climate control make a tapping or clicking noise?
The tapping is usually caused by a broken or worn flap motor lever or stop, so the motor's gear slips over. The nuisance is mainly the noise, but zone control stops working when the lever fails.
Mercedes-Benz W203: how do you recalibrate the climate control flaps?
Switch the power on and press the defrost and recirculation buttons all the way down at the same time until the lights flash. Wait about 30 seconds for the flashing to stop, and switch the power off. If the unit still does not adjust, check the temperature sensors and the flap motors.
Mercedes-Benz W203: why does it blow hot even though the control is set to cold?
There are several temperature sensors: the interior temperature sensor, the outside temperature sensor and the control panel sensor. A faulty sensor or a broken wire makes the heating behave erratically. Cold air from the centre vent onto the sensor can cause the same, so check the sensors before replacing the panel.