Dash air not working Itasca Sunova 2002

[gothic_ru]

Itasca Sunova 2002 27c Workhorse P32

Dash air fan is not working in any position. If it is in off position I can hear air noise inside the switch, in the place where a vacuum connector attached to the switch. If I choose any other position that sound disappears, though no air blown from vents. According to Service Parts Catalog I have a switch model SCS Compact Control

Winnebago no. 103930-33-702
SCS no. 083-0169

Also, I spend some time checking posts here and looks like it can be a few things:

• Faulty switch

• Relay/resistors bank

• Vacuum pipes leaking air

What would be your advice to check what is exactly broken? I don't want to throw away $250 for a switch replacement...

Thanks!

[Morich]

Depending on how difficult, I might start with pulling the switch to check the items listed. Is the switch getting power? If no power to it, I would check electrical. While there I would also look at vacuum line for any leaks. Does the vacuum suck a finger in, showing that it isn't leaking/open?
Hearing air while in the off position might make me first think of the tube leaking at the switch.
Hard to say until we get there!

[gothic_ru]

I've pulled the switch out already. What is the best way to check out a vacuum? Just disconnect the big connector for 5 tubes and check with a finger?

[gothic_ru]

So I disconnect vacuum sitch from control panel and test it with paper. It sucks air through the center tube. If I put paper to the switch the noise I heard is gone. Looks like leaking switch, right?

[Morich]

Originally Posted by gothic_ru

So I disconnect vacuum sitch from control panel and test it with paper. It sucks air through the center tube. If I put paper to the switch the noise I heard is gone. Looks like leaking switch, right?

This might sound right but then, I hate to guess and since the switch is not likely to be cheap, I might look for ways to test more. Just wild guesses on what might work but can you see a way to connect the switch to the vacuum and then check for leaks? Maybe connect it, put it in a bag, tape/tie the bag pretty airtight and watch for air to be sucked out of the bag?
Weird idea? Searching for something that doesn't cost as much as a switch!

[gothic_ru]

it's a good idea! anyways switch already ordered, I'll update my post as I replace it.

[Morich]

Carry on, sir! Sometimes we just have to move on if we expect to get things done. Not hard to get tangled up in worry so far that we miss what we wanted to do and that is not good.

[NeilV]

There are usually vacuum reservoir tanks behind the front bumper that transition from small hard plastic vacuum lines to the tanks inlets with a short piece of rubber hose which gets loose and falls off or simply rots away so those need to be checked before purchasing switches.

The hard plastic vacuum hoses due to the way they are extruded tend to fail along the seam created by the die they are extruded through and also need to be checked since when the seam fails its about the same as if you slit the tube open along portions of its length. The hard plastic vacuum hoses are not very UV resistant and tend to have a higher rate of failure where even reflected light can get to them. They may be all black or various colors such as blue, red, green, yellow, etc. The hoses may be hard to source in long lengths however they can be spliced together using rubber tubing with the same/slightly smaller inside diameter as the hard plastic tubing's outside diameter.

On my 2001 Adventurer it was a bear tracing their paths from under the dash, out under the hood, through the dog house area, along the frame and to the hidden tanks but I got it done last year. You may have to visit a few local auto parts stores by the lengths of plastic tubing along with the correct size rubber tubing should be locally available. I was only able to get black tubing and marked them with wraps of tape every 6 inches that I colored with broad tip markers to match the original color types (not an exact match).