Just picked up a well-used '86 Toronado as a winter daily driver. It's got almost 190,000 miles and I think I'm the fifth owner, but she's in decent shape. The only real mechanical problem is that it's badly in need of some new shocks/air struts.

Anyway, my heating problem. The car was blowing nice warm air when I picked it up, and after I'd driven for half an hour or so, it got too warm, so I turned down the temperature and it blew cool air. So far, so good.

Then, an hour or so later when night fell and it cooled off, I wanted some heat again, so I jacked the controls up to 75 or something.

...And there was no heat. Maxed out the temperature; nothing. Set it to cold again, then warm. Nothing. Turned the whole unit off and back on; nothing. Pulled over, turned off the car, started it again; same story. Even tapping the side of the dash like an old TV didn't work. [img]smileys/smiley2.gif[/img]

Now from looking around forums like these I've read that people's electronic dashes have given out and none of the gauges (or the HVAC controls) work. My dash is working fine, and the previous owner had it rebuilt (think < 3 years ago). The dash lights sometimes don't turn on at night, but I'm going to check out that sensor in the defrost vent for that. I can still control everything just fine, but when I set it to be warm, it keeps blowing cold air.

So, I can't see it being the dash itself, because everything else works fine. I can't see it being the heater core giving out during a 30-60 minute period where I didn't use it.

Any suggestions? Possibly the little door in the air ducts that blends the warm and cold air? [img]smileys/smiley5.gif[/img]

Hate to ask the obvious but did you change the thermostat?

Power flush the coolong system and check the heater control valve would be my first choices.


C.J.

vette: Well, while I am somewhat mechanically inclined, I don't have much experience with this stuff yet so our definitions of "obvious" are probably different. That said, I haven't changed the thermostat. I haven't had any problems with the cooling system itself. Why do you ask?

C.J.: A "power flush" sounds like something I won't be doing without a visit to a shop. Yes? No? Maybe I'm thinking of something else than you.

IF IT HAS AUTO TEMP CONTROL IT SHOULD HAVE AN AMBIANT SENSOR IN THE FRONT GRILL. I HAD A 1999 INTRIGUE WITH A DEFECTIVE AMBIANT SENSOR, WHEN I REPLACED IT THE AUTOMATIC A/C HEAT WORKED PERFECT. IS THIS POSSIBLY THE PROBLEM. ALSO IS THE FAN BLOWING AIR?

This car does have auto temp control yes. I don't think there's anything wrong with my ambient sensor though, because it displays the outside temp and seems accurate. And yes, to clarify, the only thing that is not working is the heat part of it. Well, the A/C either, but that's a separate problem (compressor's seized, got a shorter belt to bypass it). The blower works at all fan settings, and in all modes (panel, floor, defog).

To update, I figured out how to run the diagnostics on my car, and I had a few codes come up for the BCM, one of them being:

B440 - Air Mix Valve (Door) Circuit Problem

So I think my original suspicion, that the heat blender door (or, Air Mix Valve) had stopped working, is correct. And as a bonus, the part's really cheap! The problem will probably be getting in there at it...

"So I think my original suspicion, that the heat blender door (or, Air Mix Valve) had stopped working, is correct. And as a bonus, the part's really cheap! The problem will probably be getting in there at it..."





Did you fix the problem? Let me know if you can use some help as to how to get to the unit. If it's anything like an '87, I know how to take apart and re-install just about every part on that car.

Well, no, I never did, but it did fix itself! I regained control of the air temperature by some divine act I guess.

However, a few weeks later one of the CV joints went, and a couple days after that when the mechanics at the shop went to bring the car inside the garage, it wouldn't even start (cranked but no go). A few days after that, the nearly-new battery was dead. So, all of those things added up, and all that time and money didn't seem worth it for a car I spent $500 on in the first place. It was a neat little car, but I guess it was way closer to the end of its life than either I or the previous owner thought.

So, it'll shortly be sent off to car heaven, though I managed to keep the instrument panel out there in the world by selling it off. I know how hard those can be to come by, especially in my neck of the woods.

Thanks to everyone who helped/gave suggestions. I no longer have an Oldsmobile, so I don't know if I'll be around here in the near future. It was fun while it lasted.