Dash A/C operation?

SCVJeff · 07-03-2007, 10:53 PM

This is totally out of my field, so I'm going to the forum:

When I picked up the coach from storage last night I had the 1st occasion to use "Max A/C". There was very little air coming from the vents, but yet the fan was on high and I could hear lots of air moving somewhere.

I moved the control to "std." A/C and got my air back, although there sure seems to be more fan noise than air volume.

Now, I recently noticed that the little compressor in the front compartment seems to run continously. It has something to do with the vacuum routing for the front A/C, but don't know what. Is this a helper pump, or is it the only vacuum avaliable up front and needs to run? And is there a link between it running and the Max A/C not venting properly?

Thanks!

SCVJeff · 07-03-2007, 10:53 PM

This is totally out of my field, so I'm going to the forum:

When I picked up the coach from storage last night I had the 1st occasion to use "Max A/C". There was very little air coming from the vents, but yet the fan was on high and I could hear lots of air moving somewhere.

I moved the control to "std." A/C and got my air back, although there sure seems to be more fan noise than air volume.

Now, I recently noticed that the little compressor in the front compartment seems to run continously. It has something to do with the vacuum routing for the front A/C, but don't know what. Is this a helper pump, or is it the only vacuum avaliable up front and needs to run? And is there a link between it running and the Max A/C not venting properly?

Thanks!

TXiceman · 07-04-2007, 02:36 AM

You may have a problem with a damper door not switching positions when you go to MAX cool. You should be able to see under the dash, some cables and/or actuators. Have some one switch the control from normal cool to max and watch which damper moves. you may need to help it along with a little shove or you may have has one of natures little critters move in and build some blockage.

Ken

CHIPPYSGT · 07-04-2007, 03:17 AM

Check for this. Under the hood there is a round accummulator about the size of a softball. One of the small rubber hoses has come off olr has cracked and that causes that little pump to run all the time. Mine is on the passenger side.

It operates the shuttle valve in the a/c ducting and it is trying to do its job of moving that shuttle valve but it doesn't move so the pump keeps running and you don't get the max air.

It took me about a month to find the leak in mine and it about drove me nuts.

Windshield washer hose from any parts hose is the right size.

CHIPPYSGT · 07-04-2007, 03:19 AM

You don't have to get under the dash for this fix. I must have had mine off 15 times looking and it was really right there at eye level staring me in the face under the hood.

Chief · 07-04-2007, 04:24 AM

Jeff, had the same symptoms with my 06 Itasca. Turned out I had a vacuum line barely connected under the hood. WB website has an excellent write up with wiring and vacuum connections clearly illustrated. Go to WB website, resources, manuals & diagrams, service tips. Look under 2005 "Auto Heating & AC". This troubleshooting guide should lead you to the problem. Hope this helps.

SCVJeff · 07-04-2007, 09:44 AM

That's what I'm guessing, and it sounds like I'm not alone. Had I not been so tired when I posted this, it should have been obvious why the pump was running.... l e a k

Doug: I chased the line from the accumulator tank into the firewall (for lack of a better term). I assume that the small line goes straight to the A/C dash control?

I just remembered I have a hand-held vacuum pump I bought to chase timing issues in my old 454 Pace. Back in a few..

Hurrumph.. need to pull the dash cover.

CHIPPYSGT · 07-04-2007, 09:58 AM

Jeff,

I just went out and looked at mine again. I was wrong. My accumulator is on the driver's side and that wasw NOT where the leak was.

In front of the passenger two heater hoses go vertically. Clamped to them, but not attached to them is a small valve? that looks like a starter solenoid but about 1/2 that size. There are two vacuum lines running into/out of it. They are attached to a little nipple with windshield washer hose piece about 1/2" long. One of those little pieces on mine was split and caused the pump to run all the time.

Hope this helps!