Vent control

[Scotialaddie]

It seems like the vent control knob isn’t functioning properly. Off works but any other position just gives me defrosters. My guess is that maybe the position control module may be the problem. Has anyone experienced this or have any other input? Thanks in advance!

[Alan_Hepburn]

Back when we owned Ford pickups the vent s were vacoom-controlled, and the default position if you had a vacuum issue was to send the air to the defrosters. I guess it's possible that your chassis works the same, so I would look for a vacuum problem behind the dash...

[theroc]

As Alan has pointed out, it sounds like a vacuum leak where the default position is the defrost mode when no vacuum is present. This is a very common problem with many brands of motorhomes that use vacuum to operate which way air is directed pertaining to the chassis a/c and heater.

There are two conversations going on in the thread linked but follow those posts that refer to the vacuum lines and pump, etc. and it should help you diagnose the problem on a Monaco coach:

http://www.irv2.com/forums/f115/dash...ts-129027.html

[Scotialaddie]

Found the problem! It was the vacuum generator. I ordered a 12 volt replacement vacuum pump and that’s that!