Blowing hot or Cold.... HVAC

[Rallyman]

My climate control system is either hot or cold set it to 22ish and after a while it just gets hot! I have had a good look at the flap /mix motors and notice that the lower red mechanism (temperature) dosent tend to stay still - then pegs its way to hot, also HVAC off - it's a bit jittery - is this normal ?
Presuming that this isn't normal operation and the motor / positioning system is past it's best, does the dash need to come out to replace the HVAC assembly?
I have also notice that the haynes manual says that the HVAC system will need to be se in a reference condition.... anyone herd of this??

Has anyone experience this fault and cured it??

The car is starting to move into the Bangernomics part of its life now and need information before I boldly go and pull the car apart big styli

Please help, I'd like to keep my Audi, my wife is looking at getting a SAAB Aero at the moment - 250bhp and FWD don't mix.....

 

[aragorn]

Mine failed in a similar fashion.

The diagnostic mode on the climate panel has a option called something like "temperature flap error count" and this was all over the place, where as the error counts for the other two flaps were just sitting at 0.

I got another flap motor from ebay and swapped it over, need to remove the centre console and glovebox to get at it though. Dont need to remove the whole HVAC system though, the motor just unbolts and unplugs.