eatumup

I have an interesting issue with my 2001 TT. The A/C works but I am having issue getting the air to the dash vents.

Early in the day everything works fine. Once the car has been sitting out and gets nice and warm its like the flapper inside the ducting does not move to direct air to the vents.

I can hear the fan blowing and can feel a little cold air blowing out with the fan on high. Sometimes after a long while the vents will open up and blow full force. there is no change in fan noise when this happens.

I assume the problem is that the air flow door in under the dash isn't moving. Given its behavior I also assume that the air control is vacuum actuated too. However, im not confident because I don't hear a vacuum leak.

Before I tear into the dash I was hoping to get a verification and any possible advice first.

is the air flow indeed vacuum actuated or is it electronic? Before I start taking things apart is there any advise to someone who has not been under the dash of this car?