Has anyone here dismantled this assembly on a B5 or similar?

I particularly want to know the arrangement of the heater control flap. Is this made of plastic which can warp and distort, or metal, and does it have foam sealing strips around the edges?

My aircon has not worked since I bought the car, and I decided to do without it, but recently the unit arbitrarily began blowing hot air, occasionally very hot air.

I eventually found that the temperature flap positioning motor - V68, was occasionally stopping in arbitrary positions.

I have now bought, fitted, and done the basic setting on, a new motor, and carried out a final control diagnosis, but the air from the dash vents is still being heated, although the flap is definitely in the closed position. I just drove for a couple of miles, to make sure the inlet wasn't getting hot air when the car was stationary, with a thermometer in the outlet, and found that although the ambient temperature is 33º, the air from the vents is coming out at 39º, not at all comfortable.

I am guessing that the flap is not properly sealing off the hot air outlet, as a small leakage of 90º air past it could easily raise the outlet temperature by 6º.

In the absence of any other suggestion I intend to fit a shutoff valve in the hot water pipe to the heater matrix.

This worked fine with most of the cars I have owned. I don't know why a simple heating/cooling system had to be made so complex. The old systems are still probably the best.

I am seriously thinking of offing this car and keeping my VW T25, which has nearly 250,000 miles and which the A4 was intended to replace.