I have owned 2 different Winnebago class A motorhomes (1995 brave, and 2007 Suncruiser) with the Evans HVAC systems. Both have a air blend door in them to control the temperature coming out of the vents. The '95 used a cable operated door and the 2007 uses an electronic module. Both work well to control the vent discharge temperature. On the 2007 with the electronic module, it is located on the passenger side of the coach accessed from your front access door (hood). Looking inside from the front, the HVAC box is on the left as you are looking at it. On the right side of the box as you look at, there is about a 4" square box that resembles an electric junction box with wires going in it. This is the blend door control module.
I cannot tell you exactly how to test this control, but it is controlled by the temp control knob on the dash and is supposed to be proportional. It does take a short time for the discharge temp to change, but should be stable and adjustable as to the desired output temp.
There is also a door at the bottom of the box that is controlled by a vacuum servo mounted on the left lower side of the box. This door determines whether outside air is drawn into the system, or it is drawn in from inside the coach near the passenger's feet. This has little effect on discharge temp control. As I recall, mine only allows recirculated air from inside the coach when in Max cool mode.
Hope this helps-- Mick
