Cabin AC

[psheehan]

I have a 2006 sun voyager 8389mxg and can’t seem to get good AC in the cabin. I recall a discussion regarding the “control valve” under the hood going to the heater. If memory serves me I need to turn one open and the other closed?
I think it was called the Evans Tempcon valves.
Any help in understanding this valve would be greatly appreciated.