Heater Troubles?

[olin18]

I Just got my 88 GW on the road and I am still working out some bugs. I got it as is, for a real good deal, and it runs strong, there are just a few things that need a little TLC.
The Heat is right up there on the list, even more so because it is Cold here in VT, and seeing out the windsheild is important.

The trouble is that I am getting very little volume of air from the blower motor. The motor spins, and warm air does come out, But not much, and not really where I want it to. Most of the air I have comes out from under the dash. And even with the switch on defrost I get almost no air on the windsheild. Does anyone have a sketch of the duct working behind the dash, is there a way to make all available air go to the windshield?
Does anyone have suggestions as to how to get more air from the blower motor. I am going to try to get in there after work today and suggestions would be helpful.
One other piece of info... When the fan is turned on High. (the last setting) It makes a lot of noise, and not really good noise, almost like a groan. Thanks for any help.

[Iron Horse]

Sounds like a vacuume line off or leaking to the switch. If you have small hands you may be able to reach up and feel the back of it. If I remember correctly there are 3 vac. lines on the back....one goes to defroster.

[ November 06, 2002, 09:39 AM: Message edited by: Iron Horse ]

[Bob Barry]

Your heater core could be (probably is) clogged with leaves, pine-needles and other debris. That would restrict flow. Solution is to pull the heater-box and clean it out. Explanations for pulling the heater box are in the archives.

As for the ducting, there is a vacuum-diaphragm that moves the flaps that direct the air. If that hose is bad, or if the source for that vacuum hose (the vacuum ball on the firewall inside the engine-compartment) is disconnected, it won't switch where the air moves.

[olin18]

Oh man, the V word, my hands are hardly small, is it a huge problem to take the control right out of the dash. And I hadn't even thought of a clogged heater core. I will do that first, that would be a pretty easy fix to get a little more air. I think that probably while I am working on the blower, I will clean up the ground, that can't really hurt anything.

[bvibert]

My blower motor makes a pretty good racket when its on high. I haven't worried too much about it, its been working for a while now. If the core is clogged I would imagine that it could make the motor work harder and make more noise??

I don't think that the control is too hard to get out. I would check out the vacum source through the middle of the firewall behind the engine. Make sure everything back there is hooked up, I think there may even be a vacum resevoir back there. A lot of people seem to like to just start disconnecting vacum houses for no apparent reason...

[Al Johnson]

I repaired a blower motor that was making that groaning noise on high speed once. It was just gummy bearings in the motor, so I took the motor apart, cleaned, lubed, reassembled. Poof, no more noise, better blower action.

[johnwom]

Olin,

I just repaired my heater this weekend and it wasn't bad at all. It was much less tedious than replacing the boots on my plug wires.

I had a problem with the buttons staying in after I selected 'Heat' or 'Defrost'. They would just randomly pop back out.

First, if you have a/c, remove the duct on the driver's side and remove the interior light suspended from that duct, (three screws total, one on int. light, two that hold duct to dash, all in same location). I left the interior light hooked up and used it to see with instead of burning my ears on a droplight.

It may not be necessary but I took the 7 or so screws out of the instrument cluster so I could move it around if I needed to.

When you roll up underneath the dash you'll see the back of the heater control and its vacuum lines. They weren't too hard to get to for me and I have pretty big hands.

The first line I replaced was the vacuum source line. This hose is the only one that goes through the firewall and connects to a fist-sized black drum in the top middle of the firewall inside the engine compartment. This is a vacuum storage tank to prevent the heater doors from closing during acceleration.

While under the hood I also replaced the larger vacuum hose that goes from that drum to the vacuum source on the manifold or carburetor, I forget which.

Next, I replaced each of the lines from the heater controls to the vacuum motors that control the flaps in the ductwork. This wasn't that difficult either but it will require that you remove the glove box so you can get to each of the vacuum motors.

I started that process at the terminal end of each hose, (at the vacuum motors), and worked my way back to the heater controls with the new hose, then cut my new line to the appropriate length when I got back to the heater controls.

Reassemble in reverse order.

Voila! No more quirky heater controls.

About your motor, I think they all are kind of noisy and not the most powerful ever built. Maybe somebody out there knows of a way to replace it with a more powerful unit. If it ever gets to be a problem, I thought I might take my blower motor out and see if Grainger or someone carries a more powerful 3-speed dc motor that I could adapt.

I've seen on here that some guys take the blower motor out and vacuum out the ductwork from the blower motor housing. It is easily accessible in the engine compartment.

Hope this helps.

John

[bvibert]

John, he has an 88, which IIRC has the new style dash. I think the heater controls are in the middle of the dash and have sliders for the controls, not buttons. I could be wrong though. Either way your information is good and most is universial between the two styles...

On the topic of replcement blower motors I've heard that some GM blower motors fit right in place of ours. I think that I saw a post from someone here recently that did it. It may be worth a search...

[ November 06, 2002, 01:14 PM: Message edited by: bvibert ]

[Bob Barry]

Yes, an '88 had the newer dash with the center-mounted controls.

The buttons on the older units would pop out when the little lever-deal in the back would stick due to corrosion from age. WD-40 might free it up sufficiently.

[kyjman]

Look under the dash and find the little door thats not opening due to the vacumn leak....get some tie wire and tie it open and walla you will have air in the floor and the defroster at the same time....I did that on my truck and its working great now.

[RWC]

My '89 had basically the same problem, and last winter s*cked! While crawling around under my dash for something else (I don't even remember what), I ran into a dangling vacuum line from the back of the heater controls. I plugged it into what looked like a big silver vacuum canister that had a vacuum port on it, and suddenly found myself with plenty of heat! :D

RWC

P.S. Olin, where in Vermont are you? I'm going to the law school in South Royalton.

[olin18]

RWC, I am in the Burlington Area, and I love this state

UPDATE
Last night I took the blower motor out, cleaned it up, gave it a little TLC, put it back in and now it works WAY better. Probably about twice the volume of air
HOWEVER, I still don't have any heat at the windsheild :( , And my goal here is to get the heat there. I don't mind being cold, I drove my YJ last winter, I just want to be able to defrost and see.
I took the dash apart, took out the sterio to give myself a little more room (Little being the word there. I took the heater control out kind of, it wouldn't come all the way out, I couldn't really get to the back of it. I did find what I thought was a vacuum line that was just haning, but could not find a place to plug it in. I know it is the defrost motor line, because when I turn on the heat, I can here a vac sound then I can hear the little door close/open. When I switch to heat/deforst, I hear the same thing, little sucking noise... then a door swinging shut/open. But when I slide the lever to "defrost" all I hear is a sucking sound, no door.

Can anyone tell me WHERE the defrost vac motor is, or how I can get to the little door to rig it open. I know that this is probably a long shot but does anyone have a diagram? The manual I have does not cover this, and there is so little room under the dash I can't see anything. Thanks very much for any help.

RWC, Alaska to VT, that is quite a move, how do you like it here.

[RWC]

Olin, I'm telling you, just keep looking around underneath your dash. The one that I plugged in that gave me the volume of air to my defroster was silver, and the empty port was on the top of the canister. I think the loose vacuum-line was transparent, and had a rubberish flange-type end. I'll look at it when I get home today (I drove the CJ this morning) and see if I can describe it a little better.

Vermont's nice, but I admit it just makes me more homesick. I'll be going back when I graduate this May. Right now I just want some SNOW so that more trails will open up on the mountains!

RWC

[olin18]

I did see one of those silver canisters under the drivers side of the dash, but it already had a vac line with a little rubber boot on it. I took the loose vac line, and switched them, nothing really changed at all. My guess is that the silver thing that I found was for the heat that comes out on the floor under the dash. I guess what I am looking for (I gues) is the littls silver thing that runs the windsheild defroster. Does anyone know where this litte silver Ba$t#rd is? Drivers side? Passangers side? right in the middle?? I have no Idea.

[RWC]

I looked, and it sounds like you already found it. The canister on mine that wasn't hooked is a little smaller than a hand-grenade. It sits tucked underneath the dash back from the four-wheel drive actuator, and had the vacuum port on the left side, pointing up. But I SWEAR that when I reconnected it, I got windshield defrosting too! Sorry, I don't have any more productive advice. :(

RWC

[Thomas DeBusk]

I've been following this topic with great interest because the heater on my '83 Wag is similarly messed up. Mine suddenly quit switching off of defrost, but I've looked under the dash and haven't been able to find the missing hose.

johnwom: what did you use for replacement hose?

RWC: Great to see another lawyer in the making on the list. I think if more of us were grease monkeys we would have a shot at rehabilitating the profession. I know I'm supposed to like golf, but I'd much rather have bleeding knuckles, dirty fingernails, and classy wheels like my Jeeps.

Thomas

[RWC]

If your Wag is an '83, you've got a different set of heater controls. If I still had my '85 parts-rig I might be able to help you out, but sadly it had to go to the junkyard last spring. :(

I can't say I'm much into golf either. I went for the very first time last summer in DC, and I admit, it was kinda fun, but I probably spent 40 or 50 hours wrenching on projects over the summer compared to the two or three that we spent on the course. Everyone that I've worked with and everyone here at school eventually just accepts the fact that I will have grease under my fingernails at least one day per week. In fact, as I sit here in the law review office, my right hand is dirty from fixing a vacuum leak on my CJ on the drive here! :D

What's worse is that I'm going to the "environmental law school." Don't worry; I'm on our side. ;)

RWC

[olin18]

I would like to thank everyone for the help with this problem. Well Yesterday I really got into it and figgured it out. RCW was 100% correct. That one little silver Ba$tard is the only vac motor back there ( I know this because I took the whole thing apart big PITA for finding nothing) I don't know what the story is but there are two vac lines that seem like they both go in this thing, I tried them both. I ran the engine, while sitting upsidedown with my head under the dash (I hate under dash work) and switched trhough the heater selections. And BAM ! when it clicked over to deforst little vac motor moved the lever. I was pumped that it actaually work. I reached up from under the dash and there was air coming out by the windsheild. YES ! project done, I put the dash back together (PITA) I was a happy camper. Then late last night I needed to go somewhere, I was excited to turn on the defrost !!! The stupid thing didn't work. My best guess is that with the rig moving the vac pump is running all sorts of things that it isn't running while the rig sits at idel. I guess there just isn't enough vac to operate that little motor.
My solution is going to be that I am going to disconnect the vac motor, and wire tie the lever open full, so that all the air will go to the windsheild duct.
Thanks again for all the help everyone. Wouldn't even have known where to start.
I think that later maybe when I have some time I am going to build a cable lever that will move the duct lever, that will give me the choice again between heat and defrost. But for now I am going to chose to see, and just wear warm socks.
Thanks again Everyone, I will get this Waggie going like the beauty it is. Just going to take time and questions.
All of you guys, and gals are truly experts.

[kyjman]

That tie wire trick has been working for me since 1998.....try it you'll like it !!!