See also:

The spray nozzles are misaligned
The windshield washer fluid from the spray nozzles no longer hits the center of the windshield. The spray nozzles are misaligned. - Have the spray nozzles adjusted at a qualified specialist wor ...

Setting the side air vents
To open/close: turn thumbwheel 3 up or down. Side window defroster vent 1 is never completely shut, even if side air vent 2 is shut. ...

Qualified specialist workshop
An authorized Mercedes-Benz Center is a qualified specialist workshop. It has the necessary specialist knowledge, tools and qualifications to correctly carry out the work required on your vehicle. ...