Hello, I have read a couple of posts about retrofitting a airquality sensor to a A4B7 but have come up with a problem I can’t seem to find a air conditioner controller that has a air quality sensor button, seat heater and work my rear window heater as it seems that they only were available on the b6. (What the dealer seems to think)

the problem i have is i is I have a controller 8E0 820 043 AH it all seems to work except the rear window demister so I did research and that part is from a b6 with the internal relay for the rear window demister - I think and I have the upgrade with the external relay.

Can i get the external relay to work by soldering a power input into the controller so the internal relay has send power to the newer external relay OR DOES some one know the part number of the climate control that has heated seats and airquality sensor for a 2007 b7 with external relay (my only dealership can’t help)