Broken Heater - Just in time for winter!

His observation that the heater inlet and outlet hoses were both hot to touch is a good sign that it isn't.

 

It's pretty easy to tell if you have vacuum operated temp control or cable operated. The vacuum operated one usually moves very easily and if you listen it has many definite little clicks as you move it. The cable operated one is usually dead quiet except for when you move it quick and hear the blend door slam at each end of travel.

I've had several of these cables come off the heater control. They're held on by a little retainer washer over a plastic stud. The retainer may have come off or the stud may have broken. If the retainer won't stay on, I've threaded a small nut onto the stud to keep it in place. If the stud is broken, you pretty much need to get another heater control from the junkyard.

 

Okay, I took the Griswold out to the gas station and vacuumed all the leaves and crap out of the cowl area. Some debris may have fallen underneath the leaf guard, but it should be very little. I got the bulk of it, anyway.

My next plan of action was to find an HVAC diagram. I have both the original owner's manual and a Hayne's repair manual, but the best thing I could find was schematics for the chassis electrical system, including a section for the heating and air conditioning system. I can't make any sense of it, though. I'm no mechanic, and I'm certainly no electrician......lol.

I guess the next thing to do will be to remove the instrument panel and try to find out whether or not the heater lever is connected by vacuum line or cable. I have a feeling it's cable operated, wagonman. The slider moves very easily and I haven't noticed any clicks along the way.

I'm not sure exactly what I'm looking for, but I'm just gonna look directly behind the heater control and try to find the connection points. Wish me luck!

 

I have scanned the diagrams out of my FSM for you, I am going to try to PDF them via PM now.

 

Thanks for the diagrams, BigBird! I actually left for my Thanksgiving vacation a day earlier than planned, which means I didn't have time to fix the heater. I left around 11pm and got here at about 3am. The trip was cold, but I bundled up and it wasn't too bad.

Anyway, the first chance I get I'm gonna get to work on that heat controller. Hopefully I can fix it so I'll have heat for the return trip. I'll keep everyone posted. Thanks!

 

I just came in for a break from working on the car. I was getting really frustrated and needed to calm down.

Every time I take off the instrument panel, another chunk of plastic breaks off. The plastic is brittle and stiff, and 9 times out of 10 it breaks before the metal clips release. It's getting to the point where my instrument panel is sagging and barely hanging on to the dash. Needless to say, I'm frustrated.

Anyway, I removed the instrument panel and took all of the screws out of the mounting bracket holding the heater control, but I can't get it to slide out all the way. I couldn't reach behind it, so I removed the CD player from underneath so I could get easier access. This would be a hell of a lot easier if I could slide the whole thing out and see what's going on, but I can't seem to do that.

From what I can see with a flashlight, I can't tell if anything is disconnected or not. Should I be looking directly behind the heater control for the detached cable?

 

Okay, I just went back outside bound and determined to find the damn cable. I looked on the underside of the heater control and there it was! The only problem is that there is no problem. It is securely connected just like you guys said with a washer holding it down. I moved the temperature switch from 65 6o 85 and watched the cable slide back and forth. So if that's not the issue, what else could it be?

 

The other end of that cable opens and closes the flapper door inside the ducts to route cold or hot air to your vents.

 

Yep, check the other end of that cable. I would think you should be able to get to it by removing the cover panel from under the passenger side dash. Or if that fails, at least behind the glove box.

 

dont be a smarty pants..

(I may have 'skimmed'....)

 

I removed the glove box and found the other end of the cable. When I slide the temperature lever on the heater control, I can see this metal arm behind the glove compartment moving back and forth. What should I be looking for? Thanks!

 

Usually if you slide the temp lever really fast back and forth all the way, you can hear the door slam in the HVAC housing. It's pretty clear.

If you hear nothing, maybe pop off the cable maybe you can feel if the arm is really moving an internal door, or if maybe the internal door is broken?

If there's something broken internally, then you'd have to get the cover off the heater core to get at the internal door. What you've done so far is probably a piece of cake compared to the heater core cover. I've done heater cores in 4 of my cars.

I've had a similar problem with my Celebrity for the last 5 years. The temp control door that you're having a problem with is somehow interfering with the air flow direction. On cold, the air only comes out the defroster no matter what, but on hot the air comes out where you select. It is not a vacuum or control valve problem, it changes instantly with the temp lever. When I changed the heater core a couple years ago it worked fine for a few weeks. It's gotta be some kind of internal linkage gone screwy but it's such a pain to get at that it's not really worth the headache. Thankfully it doesn't get hot for very long here and I use the heat way more than the vent, and I just open the window a little if it gets hot.

 

Is this a regular heater/air conditioning or the optional automatic deal?
With the temperature control marked in degree increments it sounds like the latter?
The temp control cable goes to the programmer control lever behind the glove box IIRC?
If it is the automatic deal I'd get a Factory Service Manual and start over from the beginning with the system diagnostics.
It's best if the interior plastic is warm before trying to remove it so it isn't quite as brittle, some of that stuff petrifies and you can't do anything but hope for the best though.
On reassembly dab a little Door-Ease (wax lube stick) on any tension fit areas or clips and it will go together and come apart a lot easier.

 

When you say you moved the temp control from 65 to 85 would that not mean that you are running the air conditioning?