Community Forums

str8six · 06-24-2013, 04:07 PM

Hello - The dash AC/Heat vent system is stuck in the defrost mode. The 'door' in the main heater core box does not move. The problem is that the vacuum generator does not run. If I apply 12V from an external battery to the terminals of the vacuum generator - the pump runs, stops on limit and the defrost/heat door operates normally with the interior controls. I believe that the vacuum generator should run on demand when the engine is running.

Does anyone know where the vacuum generator gets its 12V power ??

Thanks

Alan
'04 Windsor
Sandy, Oregon

Skip426 · 06-24-2013, 05:31 PM

Should come through the dash controls , from the ignition. Have you checked all your fuses?
Seen any names on the heater housing ? I have wiring diagrams for mine , out in the coach . I'll get out and check the brand when the rain lets up.

str8six · 06-24-2013, 07:11 PM

Thanks - I checked the fuses in the front run box and looked for a fuse behind the AC/Heater mode switch: no luck. I expect the vacuum generator to be switched by the mode switch (def, heat, high/low). I do see the vacuum generator on the owners manual schematic. Perhaps there is a schematic of the heater control switch - it looks like a Ford assembly.

Alan
04 Windsor
Sandy, Oregon

AtlantaRick · 06-25-2013, 12:51 PM

Allan

I had the same issue last year. Here is a thread of how I fixed it. My original vacuum thing ran off the chassis air pump so I had to redo it to make it a self contained pump.

http://www.irv2.com/forums/f115/is-t...mp-130979.html

Now after a year it is starting to act up again and I have to bang on it to get it going. But now I know I can get a cheaper one at an auto supply place when the banging won't fix it anymore.

Rick

AtlantaRick · 06-25-2013, 03:25 PM

Whoops... I just re read your question and it looks like your pump works when it get power.... my link was based on the motor being bad which is not your case. Sorry.

str8six · 06-25-2013, 04:26 PM

Hello AtlantaRick - thank you for the link, RIRSAR described a fuse location that I would have never found - the electric vacuum pump is tied to the front step and is labeled Step/ISO. The fuse was blown.

The dash air is now working thanks to you and RIRSAR.

Alan
04 Windsor
Sandy, Oregon

H. Miller · 06-26-2013, 05:54 AM

FOR FUTURE REFERENCE....
Monaco products of this era (and many other mfg's) used SCS Frigette who is now Victory systems for all a/c-heat systems. See Victory Climate Systems - Climate Control Products for a World in Motion for parts, etc...

CoCoDave · 06-26-2013, 06:14 AM

Ooops... Just saw where you found and fixed the problem. Good job!

I'll leave my post here in case someone else has the problem and the fuse is not the cause.

************************************************

Here's what I found when my compressed-air-operated vacuum pump died.

Vacuum Pump Wires Pinched

The wires supplying power to the air valve were spliced with crimp-on barrel connectors a few inches outside the pump housing. The barrel connectors were crimped too tight and one literally cut a wire in two. You could not see the break but if you wiggled the wires in the vicinity of the splice, the pump would cut in and out.

FWIW