In Dash HVAC Duct Selector Kaput

Topic: In Dash HVAC Duct Selector Kaput (Read 1246 times) previous topic - next topic

In Dash HVAC Duct Selector Kaput

July 11, 2016, 05:48:15 pm

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 – July 11, 2016, 05:51:26 pm

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 – July 11, 2016, 06:19:03 pm

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 – July 11, 2016, 06:22:52 pm

Look in the box behind your entry step. That is where the vacuum starts.

Re: In Dash HVAC Duct Selector Kaput

Reply #4 – July 11, 2016, 06:47:43 pm

Quote from: craneman – July 11, 2016, 06:22:52 pm

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 – July 11, 2016, 07:23:55 pm

Quote from: Traveling Man – July 11, 2016, 06:47:43 pm

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 – July 11, 2016, 07:29:36 pm

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 – July 11, 2016, 07:52:34 pm

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 – July 11, 2016, 08:28:52 pm

Quote from: craneman – July 11, 2016, 07:23:55 pm

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 – July 11, 2016, 09:42:34 pm

Quote from: Traveling Man – July 11, 2016, 08:28:52 pm

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 – July 11, 2016, 10:07:57 pm

Quote from: craneman – July 11, 2016, 09:42:34 pm

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 – July 11, 2016, 10:33:17 pm

Quote from: Traveling Man – July 11, 2016, 10:07:57 pm

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 #12 – July 11, 2016, 11:13:06 pm

Obsolete Vacuum Generator

Here is my old post using the Ford type replacement vacuum pump to fix my dash vents:

Vacuum Pump Replacement

Dorman Vacuum Pump

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

Re: In Dash HVAC Duct Selector Kaput

Reply #13 – July 12, 2016, 08:59:13 am

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 – July 12, 2016, 09:06:03 am

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 – July 12, 2016, 09:18:37 am

Quote from: Traveling Man – July 12, 2016, 08:59:13 am

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 – July 12, 2016, 09:22:33 am

Thanks P & M.

Re: In Dash HVAC Duct Selector Kaput

Reply #17 – July 13, 2016, 06:30:28 am

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 – July 13, 2016, 07:53:06 am

Quote from: Traveling Man – July 13, 2016, 06:30:28 am

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 – July 13, 2016, 05:12:02 pm

There's no curtain on mine.

Re: In Dash HVAC Duct Selector Kaput

Reply #20 – July 13, 2016, 06:07:17 pm

Quote from: Traveling Man – July 13, 2016, 05:12:02 pm

There's no curtain on mine.

when the step is down what covers the box opening on a 2003?

Re: In Dash HVAC Duct Selector Kaput

Reply #21 – July 13, 2016, 07:09:36 pm

Quote from: craneman – July 13, 2016, 06:07:17 pm

when the step is down what covers the box opening on a 2003?

OEM on a 2003 is either a single air step that extends like a platform or a Kwikee 2-step Series 22 (IIRC) electric swing down model. There is no box opening.

Re: In Dash HVAC Duct Selector Kaput

Reply #22 – July 13, 2016, 07:21:08 pm

Quote from: Michelle – July 13, 2016, 07:09:36 pm

OEM on a 2003 is either a single air step that extends like a platform or a Kwikee 2-step Series 22 (IIRC) electric swing down model. There is no box opening.

That complicates the issue on advice I was giving. I guess you have to access the box from underneath the coach after all.

Re: In Dash HVAC Duct Selector Kaput

Reply #23 – July 13, 2016, 08:01:05 pm

I can't see too well up close. Are there 4 screws
that hold the mounting flanges?

Re: In Dash HVAC Duct Selector Kaput

Reply #24 – July 13, 2016, 08:44:33 pm

Quote from: Traveling Man – July 13, 2016, 08:01:05 pm

I can't see too well up close. Are there 4 screws
that hold the mounting flanges?

Yes, but you need to make sure the problem is at the vacuum generator. You could have a broken vacuum line in the dash or another issue leaking the vacuum. I used a vacuum gauge tool that pulled vacuum on the line coming out of the can to the dash and made sure it had no leaks. If you look at the post I did you can see the tool. If you don't have anyway to test that the hvac vacuum system is good. You might be wasting your time on the vacuum generator, it could be good. If you can get air pressure up over 100 psi. and take the line off the vacuum can to the dash see if there is vacuum coming out of the port on the can. If so the generator is working.

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