[s-cars] Climate Control Vents - Stopped working

[mdbishoff at attbi.com]

Hi guys - My wife swears she didn't do anything to upset the car, but I think
she did something. All the middle blower vents on my '92s4 have stopped
working. When you press the button on the right climate control display to
blow air from what the manual refers to as "outlets 3 and 4", nothing comes
out. I fiddled with the individual vent open/close controls, but that didn't
help.

What should I look for to figure this out and how much work is it?

Mike