Heating and cooling interior on 2006 Audi A6

During warm weather I receive cold and hot air from vents when the auto temperature control is calling for cooling. The hot air can come from the side or center vents while the cooling is mostly from the center. I am forced to turn off the auto temperature controls and open the window. Any thoughts?

Asked by for the 2006 Audi A6
This is a known Audi fault. There is a valve to control the heat directly from the AC, heater unit which due to Audi arseing up by not flushing the engine coolant system as new meant swarf got into this delicate unit and basically wears it out too fast. I have tried a repair but basically it needs replacing and Audi will NOT pay for it. I am very angry at that. One thing you can try is cycle the heater. Set temp to max for 5 secs then right down to min. It should move the valve and bring the temp down for a while. May need to repeat this every five minutes when they are really worn as mine is. Long and short is about 500 to fix, they may also replace the temp sensor too. It is a good all round car, let down by this incompetence.
Audi have a TSB on this, which is their internal method of labeling known faults and repairs.