I have a 98 A8 Quattro, I just took it to get the A/C checked (the center vents vents as well as the passenger vents blow cold air, but the driver's side vent doesn't, it also takes a quite a while to cool down) the first independent shop I took it to didn't have the fitting to test it, the second is telling me that my flap control module has gone bad. All they could tell me is that the module is very expensive and hard to get to, I looked online and found it for a reasonable price, perhaps I could change it myself. Has anyone had this problem? Where is the control module for the flaps? I don't want to take it to the dealer until i have exhausted every possibility since they're so expensive.