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Topic: In Dash HVAC Duct Selector Kaput (Read 1570 times) previous topic - next topic

In Dash HVAC Duct Selector Kaput

No matter where I put the selector switch on the dash HVAC control knob the air only comes out of the defrost ducts on top of the dash.

I can hear the switch in the heater box clicking at each selection,  but nothing changes.  Is what I need to check accessible by opening the generator cover?
I'm thinking it's a vacuum problem.  Either something came unhooked on the roads in Connecticut yesterday, or a vacuum switch needs replaced.

Re: In Dash HVAC Duct Selector Kaput

Reply #1 –
Yup, lack of vacuum means that the default position (defrost) is chosen.

Most (read not all) Foretravels have a separate 12 VDC vacuum pump up front.  So, first thing is to find your "source of vacuum".

Re: In Dash HVAC Duct Selector Kaput

Reply #2 –
I have removed the big cover behind the instruments,  radio, etc. but I cannot locate anything pertaining to vacuum, like lines or a pump.  How much of the dash do I have to remove?

Re: In Dash HVAC Duct Selector Kaput

Reply #3 –
Look in the box behind your entry step. That is where the vacuum starts.

Re: In Dash HVAC Duct Selector Kaput

Reply #4 –
Quote from: craneman –
Look in the box behind your entry step. That is where the vacuum starts.

Thanks Craneman...........I found it.  But I cannot find any reference to it in any diagrams.  Don't know
where the fuse/relay is or how to know if the pump is working.

Re: In Dash HVAC Duct Selector Kaput

Reply #5 –
Quote from: Traveling Man –
Thanks Craneman...........I found it.  But I cannot find any reference to it in any diagrams.  Don't know
where the fuse/relay is or how to know if the pump is working.
Is it an electric motor or does an airline go to a square box?

Re: In Dash HVAC Duct Selector Kaput

Reply #6 –

This tool will help find many dc electrical problems I keep one in the coach, one in my crane and one in my shop. It can power the motor if it has one or find missing grounds or hot wires.


Amazon.com: Power Probe III - Black: Automotive

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: In Dash HVAC Duct Selector Kaput

Reply #7 –
Even if you have vacuum the controllers that make flap doors actuate may be failing.  we had both things go bad at the same time.  a new electric vacuum pump (right out of a Ford something) and a switch to bypass the flap controller.  Switch on, all defrost. Switch off, the other vents.  Sounds like a vacuum problem if all are not working.

Re: In Dash HVAC Duct Selector Kaput

Reply #8 –
Quote from: craneman –
Is it an electric motor or does an airline go to a square box?
Airline to a black box.

I found information on Barry Beam's tech help
concerning replacement of the black box with a Ford pump. I'll try and do what it suggests
tomorrow.  Would like to start with something easy like a fuse or circuit breaker but can't find any reference to one.

When does my vacation start?

Re: In Dash HVAC Duct Selector Kaput

Reply #9 –
Quote from: Traveling Man –
Airline to a black box.

I found information on Barry Beam's tech help
concerning replacement of the black box with a Ford pump. I'll try and do what it suggests
tomorrow.  Would like to start with something easy like a fuse or circuit breaker but can't find any reference to one.

When does my vacation start?

Do a search on obsolete vacuum generator I posted how to repair it for under $10.00
You could just add another check valve between the box and the can and get the same results. I was just curious as how it worked when I did mine.

Re: In Dash HVAC Duct Selector Kaput

Reply #10 –
Quote from: craneman –
Do a search on obsolete vacuum generator I posted how to repair it for under $10.00
You could just add another check valve between the box and the can and get the same results. I was just curious as how it worked when I did mine.

Can't find anything using search function.
Got a link?

Re: In Dash HVAC Duct Selector Kaput

Reply #11 –
Quote from: Traveling Man –
Can't find anything using search function.
Got a link?

I don't know how to link my posts. Type "obsolete vacuum generator" in the search box then change "this topic" to "entire forum"

Re: In Dash HVAC Duct Selector Kaput

Reply #13 –
Craneman,  I was able to complete the search function and find your thread.

Thanks to all that responded.

CAN ANYONE TELL ME WHERE THE FUSE FOR
THE VACUUM GENERATOR IS?

Re: In Dash HVAC Duct Selector Kaput

Reply #14 –
All the electrical does on the vacuum generator is stop the air flow that makes the vacuum. If you have no power you would have a continuous air leak at the box, and vacuum. In order for the vacuum generator to work you must have air pressure. I hope someone has a electrical schematic to tell you where the fuse is, but I don't think that is your problem.

Re: In Dash HVAC Duct Selector Kaput

Reply #15 –
Quote from: Traveling Man –
CAN ANYONE TELL ME WHERE THE FUSE FOR
THE VACUUM GENERATOR IS?

Tman,

That is an auto reset breaker hid behind the kick panel just to your right side as you come in the front door.  It should be on breaker 11 but if that breaker is bad you loose power to the HWH cpu also, as they share the same breaker.

Pamela & Mike

Re: In Dash HVAC Duct Selector Kaput

Reply #16 –
Thanks P & M.

Re: In Dash HVAC Duct Selector Kaput

Reply #17 –
I was able to hear air escaping from inside the black box, but probably can't remove it for repair as the coach is too low and I left my jack stands at home.

Re: In Dash HVAC Duct Selector Kaput

Reply #18 –
Quote from: Traveling Man –
I was able to hear air escaping from inside the black box, but probably can't remove it for repair as the coach is too low and I left my jack stands at home.

When the step is down I removed mine from behind the curtain without getting under the coach.

Re: In Dash HVAC Duct Selector Kaput

Reply #19 –
There's no curtain on mine.