On your car, F11 powers the Blower Motor Controller and F10 powers the Pushbutton Controller. Also, did you try the fan mode in High rather than Auto?

If these don't produce anything, then the problem may be broken solder joints in the Pushbutton Controller. The circuit boards are arranged in an "H" pattern and the solder joints, where they meet, are prone to cracks. Resoldering may be needed. Do a search for "resoldering" and "pics" or "photos" for more details. Not a difficult job but if your not comfortable with a soldering iron find a buddy who is and he can have it fixed in less than an hour.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )