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Old Grape · 05-02-2019, 03:53 PM

Good Afternoon,
I just picked my 06 Tour up from the repair shop after having new sway bar bushing put in to pass inspection. On the way to drop it of dash AC/Heater worked as usual. Not a lot of air but ok. Fan always louder than amount of air it blew out. Well when I picked it up the fan still sounds like it is blowing up a windstorm but not one spec of air coming out of the dash vents. So I looked under the front end and the area where under the dash is completely sealed off from where they were working. I once had a similar problem in my old F150 where an actuator switch went bad and would not open up an internal vent door somewhere upstream of the dash vents. Has anyone had a similar problem in their coach and if so any ideas on how to fix it?

Carlos Marti · 05-02-2019, 04:14 PM

Do you have air blowing out the defroster vents. If you do, you may have a vacuum problem. Either with a hose or the vacuum pump or reservoir. These are on the firewall when you open the front.

Old Grape · 05-02-2019, 04:23 PM

Quote:

Originally Posted by Carlos Marti

Do you have air blowing out the defroster vents. If you do, you may have a vacuum problem. Either with a hose or the vacuum pump or reservoir. These are on the firewall when you open the front.

Thanks. I just checked and all the air is going up the defroster. I felt around under the das where I could and there is a module with and actuating arm I can move and the air comes out the dash vents when I move it but it won't stay there. Guess I'll be taking off the dash panels this weekend.

Any easy way to figure out what is leaking?

Carlos Marti · 05-02-2019, 05:11 PM

No. The vacuum stuff isn't inside, it's outside, above the generator. And it's vacuum that operates the inside mechanism. Start outside on the firewwall above the generator.
On edit. The problem is usually a broken hose.

Old Grape · 05-02-2019, 06:31 PM

Thanks for the clarification. I can take a quick look tomorrow when it gets light again. With that info it is very likely that the techs hit something while working on the sway bars depending on if they were reaching over the side of the generator to get at the top joint.

cbeierl · 05-02-2019, 07:22 PM

You might also check out this thread (complete with pictures): Pump noise under the hood??

If there's a vacuum leak the system will default to defroster only (for safety). If you're getting defrost air but not dash or floor air this could be the cause.

Old Grape · 05-03-2019, 08:13 AM

Thanks for the link. I read thru it and then went out and found the items pictured. There are no apparent hose/tubing leaks/cracks. So I'm back to square one. Each canister that is shown in the pictures have a plunger on a rocker arm of sorts. I would assume that those are supposed to actuate to modify where the air goes. I manually tested them and they both will move. The silver canister shoots up a puff of dust when I push it down. Is there a way to test the canisters?

Old Scout · 05-03-2019, 08:29 AM

….detecting a dash vacuum leak is a bit like finding a water leak in your house or rig....the usual cause of a vacuum leak is at a hose connection.....first things first--is the vacuum pump actually creating a vacuum?...then trace down the line to each connection [including the accumulator tank] to see if vacuum is still present...the membrane in the actuator could also have failed or the door connecting arm broke but these are less likely....