B56

hi guys i picked up a 2001 s8 recently and noticed the hvac System is a bit complex. Its seems nice if it works properly which im not sure if mine is.

1) when i press the center vent button on the passenger side of the hvac unit nothing happens. Air does not come out of dash vent on the passenger side, the light on the button does not come on and that side still stays in auto mode. So basically pushing the button does nothing. Pushing the upper dash button and/or footwell button works fine. There are no faults in the head unit yet as per my friends vagcom diagnosis.

2) i dont feel air coming out of the rear door vents in auto or manual mode. Is this a flap issue?

3) is there a way to sync the temp on both sides so if the driver adjusts the temp on the driver side, the passenger side temp will adjust to the same degree?

Otherwise it seems fine. Ac blows cold. Heat blows hot. Just wish i could get the airflow to work properly.

Razman

Respectively, here are my thoughts/opinions:

1) It would appear that the button contacts are bad - not sure what the solution is there (replace the panel??) but that would be my first guess.

2) If air is coming out of the front side vents (the ones by the doors) then you should be getting air from the B column vents for rear passengers. Check the ductwork in the doors; my driver side duct is missing so I'm planning on replacing that soon. I don't think there are any flaps anywhere - so if the side front vents are working, the rear ones should be also.

3) I don't think so.

See this link: https://www.audiworld.com/forums/a8-...sited-2798895/

I just went through the codes and found why my system sometimes switches to some internal circulation mode. I can hear the fan running but I get no air. By adjusting #30 to 00 it was fixed, we'll see how this plays out when I'm driving. It usually happens when the temp control reduces the fan speed (when the interior reaches the indicated temp) or if I switch from A/C to Economy mode (or vice versa).

Raz