Okay another newbie '04 e320 question - read and re-read the manual and still don't understand what the center dial (with blue) does between the two center vents. Supposedly it has something to do with cold or hot air - but when I move it up (open) or down (close) nothing appears/feels happens.

Anyone??

Thanks!!

 

This is a well worn question that has been asked many, many times.

The centre dial purely supplies fresh air. Not heated and I believe not air conditioned.

US members describe it as a 'European thing'

Happy motoring

John
Sunny Torquay

 

The blue wheel opens and closes a "fresh air" vent electrically, so don't expect an instant response to movement of the wheel. It would presumably let us have cool air from outside at the face through the center vent while the heat is on elsewhere. (I see no value in the summer.)

Importantly, however, it only operates when the system is in "manual mode", meaning the air discharge position is chosen manually by using the circular arrow buttons to select which outlets are in use throughout the system.

It does work, but I've found it's of limited if any value. The W203 system was a little more intuitive and activated more quickly manually. Likewise, the W203 dashtop diffuser was more effective than the dashtop diffuser position on the W211.

 

 

The diagram shows that the choice is between A/C air or A/C plus heater air. Thumb wheel is M2/22.