Dash heater and A/C controls, not operating correctly

[JohnnyJ]

Hello all... first post here!

I've lurked here a few times, and thought it best to sign up... ask some questions, and offer advice where I can. Great site.

With that...
I have a '99 Winnebago Chieftain.
Recently, the heater and a/c controls aren't working properly. I believe there's a problem with the vacuum portion of the system, simply because I switch from panel to floor to defrost, and there's no change. I opened up a portion of my dash, and can move the diaphrams by hand... but, the rotator knob... does nothing to divert air where it needs to be.

Is there a vacuum pump, or something I need to find to test (for vacuum)? There'd be no reason for it to not work, meaning nobody with their greasy paws in there stumbling around other then me. I checked all the lines, and they seem connected and leak free. "Seem" to be anyway.

Anyone with a location of the vacuum pump? What it looks like...etc.etc?

BTW, the A/C kicks on when in A/C mode... I just can't get it to divert correctly. Everything else seems to be working as it should.

Help is appreciated!

[BFlinn181]

:welcome:

If it is a diesel, it would need a separate vacuum pump since the engine doesn't produce vacuum. On a gasser, a vacuum hose from the intake manifold creates vacuum for brakes and all other vacuum powered devices, including the HVAC controls. You'll have to trace the hoses from the dash controls to the engine, looking for any broken or leaking connections. A vacuum gauge can diagnose the issue. Good luck with it.

[JohnnyJ]

Wow.. that was fast!

Originally Posted by BFlinn181

......On a gasser, a vacuum hose from the intake manifold creates vacuum for brakes and all other vacuum powered devices, including the HVAC controls. You'll have to trace the hoses from the dash controls to the engine, looking for any broken or leaking connections. A vacuum gauge can diagnose the issue. Good luck with it.

It's a gasser (V10), so I'll pull the dash around the climate controls... and trace some hoses to the engine manifold? Or vice-a-versa?

I understand the vacuum coming from the manifold, but... I'm sure it leaves the manifold via a black rubber hose... and then, connects to what? I'd assume there's got to be something between the manifold and climate controls, that would operate the proper amount of vacuum... or....?

I don't have a vacuum gauge to test for leak down... so, I'll first have to do all this "testing" visually. I'm not familiar with HVAC whatsoever (however I catch on quick), but if you lead me in the right direction (a bit more detailed) I can run with it before I come back with more questions.

[F239141]

there should be a smaller line goes off the intake manifold through the fire wall to the HVAC system. If you can see the HVAC system look for the vac line, if you find it start the motorhome take the line loose, you should hear a hiss along with maybe a increse of RPM on the engine, if not lick your finger and put it over the line and see if you feel any suction.

If you get neither of them try to trace it, prob be easy with the dog house off. You can also listen for the hiss of a leak with the engine on and the dog house off


also your blend door could be broke and causing that problem too

[JohnnyJ]

I'm also reading more and searching for more info on this...

Thus far, finding help and with pictures from these threads;
http://www.irv2.com/forums/f101/vacu...one-44852.html
http://www.irv2.com/forums/f101/how-...ump-32272.html

["007"]

Welcome to the forum.
If you have the EVANS System than these diagrams may help you out.
If you do have the Evans than this link will bring you to more info.

[BFlinn181]

HVAC stands for Heating, Ventilation Air Conditioning, short hand for the functions of the dash controls that control that stuff. I'd start at the dashboard and work back to the engine. Their is usually one main supply hose to the dash controller, then the climate controller switches vacuum to the various 'biscuits' or diaphragms that actually pull or push vents open. If any of these hoses or diaphragms is leaking, it can stop the vents from opening or closing properly. By the way, if it is leaking, the usual thing is for all air to be diverted to the defrost vents rather than the dash or floor vents. The main supply hose usually goes through the firewall to a vacuum reservoir that is often a black plastic tank to 'store' vacuum. That tank is then connected to a hose that goes to the intake manifold or another multiple connector that branches from the manifold. There might be a diagram of the environmental controls, including the vacuum hoses under the hood somewhere. Here's a link to an article on HVAC checking.

How to Repair Car Air Vents Stay in the Defrost Position - 2CarPros

[wa8yxm]

I will add one thing.. The vacuum line is usually a black plastic line that looks for all the world like a wire, not a hose (it is that small) this can make it hard to trace, what's more it may be bundled in a wire loom as it passes through the dash and runs from here to there.

The most common disconnect place is the dash valve,, but the engine end IS possible.

[JohnnyJ]

Originally Posted by BFlinn181

HVAC stands for Heating, Ventilation Air Conditioning, short hand for the functions of the dash controls that control that stuff. I'd start at the dashboard and work back to the engine. Their is usually one main supply hose to the dash controller, then the climate controller switches vacuum to the various 'biscuits' or diaphragms that actually pull or push vents open. If any of these hoses or diaphragms is leaking, it can stop the vents from opening or closing properly. By the way, if it is leaking, the usual thing is for all air to be diverted to the defrost vents rather than the dash or floor vents.

Thanks for being more detailed... but, this part... I got.
And yes, my vents are all diverted to DEFROST.

Originally Posted by BFlinn181

The main supply hose usually goes through the firewall to a vacuum reservoir that is often a black plastic tank to 'store' vacuum. That tank is then connected to a hose that goes to the intake manifold or another multiple connector that branches from the manifold. There might be a diagram of the environmental controls, including the vacuum hoses under the hood somewhere. Here's a link to an article on HVAC checking.

How to Repair Car Air Vents Stay in the Defrost Position - 2CarPros

Ahh haaa!
This is the kind of info (accurate to my needs) I was looking for!

I went and again, traced the vacuum lines from the engine. There's lots of them (red, green, white)! BUT, they all (eventually) lead down to a large black box that's in front of the passenger tire and mounted to the outside of the frame rail.

I went and followed another vacuum line, that eventually (inside the engine compartment and just above the radiator/fan assembly) goes from a red vacuum line to a black hose (hose is actually wiper water hose). That black hose pops into the front hood area, and goes to the black plastic tank (softball) that you speak of. From there, it leaves the tank as a smaller black hard plastic line (similar to the vacuum hoses, just a tad smaller) and disappears back into the engine compartment...or, somewhere unknown.

However, I tried to trace the black line... and it was disconnected and was easily pulled back into the front hood area (where my black ball tank is). SO....

That small black line, looks like it came out of a female orifice of some sort because it has a tiny bit of sealant(?) an inch back on the line from the end. As-if it was inserted into something, and the sealant was there to help it stay.

The problem now lies... in finding where it plugs back in! If I had to explain... it came from the drivers side. That could be almost anywhere... from up towards the climate controls, to something below the dash... to somewhere in the drivers side of the engine compartment. I'll guess dash (climate control area), and go look further.

ANY IDEAS what I'm looking for to plug it into?? I've got my fingers crossed this was the problem.

[JohnnyJ]

Originally Posted by wa8yxm

I will add one thing.. The vacuum line is usually a black plastic line that looks for all the world like a wire, not a hose (it is that small) this can make it hard to trace, what's more it may be bundled in a wire loom as it passes through the dash and runs from here to there.

The most common disconnect place is the dash valve,, but the engine end IS possible.

Ah ha..!! More perfect info... and yes, I found THIS line we speak of. And yes, it seemed to have been disco'd.

I'm heading back out to the RV, flashlight in hand.

[JohnnyJ]

WELL WELL....

THANKS to you folks here on IRV2, I was able to easily and quickly fix my dilemna!! This site, and the users... are A #1!

I found the problem, when I peered deeper behind the dash. It's a MESS of wires down there, and I'm not able to take too much apart to see where things are... or where they are going. BUT, what I was able to do was find the skinny black vacuum line from the control panel (dash climate control panel) and how it disappeared down under the dash. I pulled on it, and it eventually came up... with nothing attached. Just a skinny little black vacuum line.

(and to note; When I say "I pulled on it"... visualize a very slow gentle pull. Almost no resistance. Not some barbarian neanderthal yanking away... )

I looked further, and noticed what looked to be a check valve with female rubber ends. And I have no idea how I saw it... it's dark, and I've got a bright flashlight but it's still a mess behind the dash. Come to find out... this valve looking thing fit the vacuum line perfectly. A HA!! I'm onto something.

I had to try and find the hole in the firewall, with the wife inside shining light from under the dash or around the dog house (removed or not)... I couldn't find any hole where this vacuum line could have made it through. I got out my drill, and drilled a hole just large enough for the vacuum line (next to an existing screw hole for rubber covering, between hood area and engine compartment) in the firewall. Routed the line, connected it... AND WHA-LA, IT WORKED!!!

Oh boy... I'm so excited. You guys/gals have no idea how long I've not had dash/panel A/C or heat. Thankfully, our climate isn't too bad or never too extreme. Even though, from 40° to 95° is usually my travelling temps.

[bachler]

I had Mine apart. Removed the front cap off the motorhome. It was quite a Job.. The heater Is interesting to say the Least. The heat is Blown through the air conditioner core, They are stacked. That is the reason for the Air valve and the H heater valve; When they work at there best they are Marginal At giving out enough heat so the wife don't need a blanket. Some may dissagree; Here are the facts ;; the Heater core is Appx. 6" by 14" that is susposto heat the front of the coach;;;; My my Get real; IT will be warm in front of the outlets. Thats It.. We added a rear heater That solved the cold coach problem While driving... As running the furnace while driving, Is not wise. They have been known to flame out and burn up the side of the coach. Life is good. My posts are our experiances;;

[JohnnyJ]

Originally Posted by bachler

I had Mine apart. Removed the front cap off the motorhome. It was quite a Job.. The heater Is interesting to say the Least. The heat is Blown through the air conditioner core, They are stacked. That is the reason for the Air valve and the H heater valve; When they work at there best they are Marginal At giving out enough heat so the wife don't need a blanket. Some may dissagree; Here are the facts ;; the Heater core is Appx. 6" by 14" that is susposto heat the front of the coach;;;; My my Get real; IT will be warm in front of the outlets. Thats It.. We added a rear heater That solved the cold coach problem While driving... As running the furnace while driving, Is not wise. They have been known to flame out and burn up the side of the coach. Life is good. My posts are our experiances;;

The heater isn't really a problem... it works well in my RV.
In fact, if the dash heat isn't doing the trick we turn on the rear heat and it gets nice and toasty (rear heat - is from the motor water... not the coach furnace). Never had a problem with "heat". Only cooling the driver and passenger adequately.

[JohnnyJ]

Upon further investigation....

I was recharging my A/C when I found a blue vacuum line coming from the dash, through a rubber grommet with other wiring into the front hood area. It's either melted, or cut at an angle... and wasn't connected to anything.

Should I be looking to see where this connects as well?
I can't seem to find a good schematic for this kind of thing, and am at a loss. It either does not connect to something, or it does... and I need to locate it's connection point.

Any ideas?!?!

EDIT: Just found more info on the same subject;
http://www.irv2.com/forums/f23/blue-...ne-132858.html
http://www.irv2.com/forums/f22/vacuu...rs-139264.html

[F239141]

Originally Posted by JohnnyJ

The heater isn't really a problem... it works well in my RV.
In fact, if the dash heat isn't doing the trick we turn on the rear heat and it gets nice and toasty (rear heat - is from the motor water... not the coach furnace). Never had a problem with "heat". Only cooling the driver and passenger adequately.

Dash Air is just about pointless ..... I always run the genny with both roof airs set to 68 (my normal temp) some times run the dash air too with the roofs

[JohnnyJ]

Originally Posted by F239141

Dash Air is just about pointless ..... I always run the genny with both roof airs set to 68 (my normal temp) some times run the dash air too with the roofs

That's what I've been reading... Bummer.

I am happy to say, since my last post of "where does the blue line go"... I found the diaphram/vacuum thing on the ac/heater box thing (so technical... I know) and ran to Napa... got some rubber hose, and fixed the missing vacuum line.

I got the AC to finally utilize "max" and get down to 43.5°F from 75° ambient.

I'm happy with that!

[BFlinn181]

You can also improve the A/C by installing a shut off valve in the heater hose. Often the valve will leak a little, allowing hot water into the heater core to compete with the A/C. Something similar to this: 1/2 in. Brass SWT x SWT Full-Port Ball Valve with Drain-VBVFSWA3B at The Home Depot
Perhaps in a different size or ends according to what heater hose size you have. The valve is best if in the 'inlet' side, to stop the coolant before it enters the heater core.

[JohnnyJ]

Originally Posted by BFlinn181

You can also improve the A/C by installing a shut off valve in the heater hose. Often the valve will leak a little, allowing hot water into the heater core to compete with the A/C. Something similar to this: 1/2 in. Brass SWT x SWT Full-Port Ball Valve with Drain-VBVFSWA3B at The Home Depot
Perhaps in a different size or ends according to what heater hose size you have. The valve is best if in the 'inlet' side, to stop the coolant before it enters the heater core.

I've read about this "MOD"...
Have a picture, or example of which hose and how others have installed?

... would the valve end up under the doghouse, or under the hood area?

[F239141]

Originally Posted by JohnnyJ

That's what I've been reading... Bummer.

I am happy to say, since my last post of "where does the blue line go"... I found the diaphram/vacuum thing on the ac/heater box thing (so technical... I know) and ran to Napa... got some rubber hose, and fixed the missing vacuum line.

I got the AC to finally utilize "max" and get down to 43.5°F from 75° ambient.

I'm happy with that!

When I was real little we had a 1978 24' Minnie Winnie, the cab air on it would cool the entire rig, we upgraded to a 1982 28' Allegro, and the cab air would not cut it down south in summer. Genny and 1 roof did just fine. Now there is no chance cooling 36' with the cab air, I will say its nice to suplament your roof air(s) its nice to have that cold air blowing on you too in south Flordia in July.

Maybe your average person can get away with 1 roof air, but I like it COLD!!!! ....... Now I will say, it sure is nice in the spring/fall/warm winter day to run with the windows open

[F239141]

Originally Posted by JohnnyJ

I've read about this "MOD"...
Have a picture, or example of which hose and how others have installed?

... would the valve end up under the doghouse, or under the hood area?

what ever is easier for you, I would guess under the "hood" is better than the dog house but if you are cooling to 43 with 134a freeon, i think you are ok, If you were kickin it old school with 12 that number would/should be lower,

If you decide to do it just anywhere along 1 heater line, I would try near where it goes into the HVAC "box" just make sure there is no branch lines going to something else