When you dig into the dash of a Mercedes, you'll find many strange things Wait until you have to sort out problems with directing air to the proper vents.

When that blower/sucker is working properly, it should be able to hold a strip of tissue paper over the vent. not a whole sheet, just enough to cover the vent. Make sure it's not static holding the tissue in place.

Sixto
91 300SE
87 300SDL
83 300SD