Right rear passenger only blowing hot other 3 zones ok what could be the problem if it is fuse where it is

 

I recently purchased an 07.

My driver side rear AC is blowing Cold only, and the passenger side is luke warm.

2 different Audi dealerships said it could be AC Freon Charge/Leak. I had the AC checked and the pressures were fine.

The other option everyone has told me is blend doors. I would like to try to find a diagram before I start taking panels off and checking individual servos.

Anyone got any suggestions?