E-450 dash air fix
My Coachmen MH is on a Ford E-450 chassis. Dash air went out, only blows through the defrost vent. Ugh.
So after a lot of research I found that Ford, in its infinite wisdom, runs the vacuum line that runs the system through the AC system...where you cannot get to it. Coat to repair at the dealership is BOING because they disassemble the whole system to replace one vacuum line.
So here is the fix
Remove the engine cowl inside the cab. There is a RED vacuum line that runs up to the front of the engine compartments, transitions to black (you can test for vacuum there-should have vacuum with the motor running). Line runs through the AC and out just above the floor on the passenger side (check for vacuum there-won't be any). Disconnect the red line, run it through the dash area (will probably have to drill a small hole and seal it, connect to the black line on the passenger side. A half-day chasing vacuum lines, etc and you have it does e for a few bucks.
Hope this helps someone.