I am having the very same issues as everyone here the 2005 Audi A6 3.2 blows hot air in the sid vents while a/c is on and center vents blow cool air and the rear vents also blow hot air. What causes this issue and how can it be fixed and more importantly how much does it cost to fix?

 

sorry to hear that, maybe you can use computer read data and analysis about the fault.

 

need help with this problem too. does anyone know what it could be.

 

is there some that can forward the linknto the fix so that my wife still ride with.me in my car.....thank you thomas.bezanson@gmail.com

 

It's is the 2 stainless steel solenoids under the hood by the coolant tank. You need to remove the cover and clean those stainless steel cathodes. They get corrosion and the magnetic field won't activate the coils when the temp sensor sends a signal leaving g them stuck shut with heat from the heator core. There are videos on YouTube. Minimal work to correct.