Fan not blowing into interior
 

Today I noticed that I didn't get any air either hot or cold inside the car. I can hear the fan running, but there is just a really small amount of air actually coming out of any of the vents. I was thinking a valve isn't opening, but has any one experience with this problem?

Edit: It was just sunny outside, and I could hear the fan running powered by the solar roof, but the same problem no air actually in the interior.

Flaps are probably not moving and air is going down under dash where you cannot really feel the flow. If you have VCDS you can check for fault codes. If you exercise the flaps with VCDS output testing they often work OK for a while after that. You can either change or clean the flap control motors to restore full functionality but replacements are a bit expensive and not easily accessible to remove.

Blower motor?
 

Not totally sure this is relevant, but my solar-panel sunroof in the current A8L I own managed to wear out the dual cylindrical blower motor ... I could hear the fan running, but the output from the vents was like a 3 year-old trying to blow out the candles on a birthday cake. Prior to this, the unit did made a very slight whining noise but you could only really hear this outside the car, to be honest.

After much rooting around, I discovered that the central metal (copper?) ring/commutator was worn out and required replacement. A quick trip to the forum's sponsor and a replacement used blower unit (around £100) was sent to me. Fitting it was a bit of a pain but full service was restored instantly. "It looks like two small washing machine drums fitted back to back" is the best description that I can offer.

(Apologies if I've got the wrong end of the stick - Ainars is a knowledgeable chap and he's probably right)

P.S. A8Parts did tell me that the blower motor on solar panel sunroof-equipped cars do fail more regularly due to almost constant use - even with our inclement weather.

Thanks both, unfortunately I haven't got VCDS, but I'll go and disassemble some stuff to look if I can see anything.

Just ro add my 2p.....had a similar issue myself when i got my car.
There is a flap above the previously discussed blower motor, this was stuck about 20% open on my car leading to weedy flow in the cabin
Flap motor replacement solved the problem