My 54 plate A4 Avant TDI 130 has got an intermittant fault (but becoming more frequent) where it will only blow extremely hot air on the passenger side. It doesn't matter if the climate control is set to low, aircon on or off, the result is still super heated air. I have taken it to an Audi specialist who linked it up to the software but didn't find any fault codes (and didn't bother investigating further).

Looking back through the forum it seems that several people have had a similar fault where one side will only blow cold air, caused by a failed motor behind the glovebox. Could this also be the cause of my hot air problem?

If so, what part would I need to get and how easy is to replace myself?