Pete, ya gotta remove the whole center console so you can get to the little duct that connects to the ducts that go to the floor under the back seats. You'll see what I mean, but the central flap motor is behind that.
Oh, and if you have a 96 it's a little different.
06 A4 Q 2.0T - 115,000 miles
99.5 A4 Q 2.8 - 222,000 miles
Hibiscus Red Mica R.I.P.