I am really confused. The part on the ceiling where the air comes out (called an air distribution box), does it note have 2 knobs that looks something like the one in this link https://www.reese-hitches.com/products/Coleman_Mach_A_C_Air_Distribution_Box,RV-64521.
Depending on the year it may vary, but I have never seen one with just one knob.
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SC