'99 Regal heater issue

At the perfect time of year, my 99 Regal LS started something naughty this morning.
It was around 50 degrees this morning and I set it at auto for 73 degrees.
After about 5 minutes I noticed it wasn't getting warmer. I noticed it was set for 3 ticks out of 6 to the Floor so I bent down and felt cold air coming out (unwarmed). "That's not right." I then manually set it for 90 degrees to the floor at full fan and it was putting out cold air.
Later today, I did some testing and found this. If I turn off the system for about 5 minutes, then go back to auto or manual mode, warm air will come out for about 15 seconds (it seems longer if the system has been off for longer, like it's building up or something) and then it turns cooler or cold again (not conditioned).
Does anybody have an idea as to what part(s) is/are going? Hopefully it's something quick and inexpensive.. :)
Thank you for your help!
--
Michael Sovitzky, MCSE: W2K
C&G Consulting
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First question is does your Temperature display flash? If so, take the car to a dealer and they can retrieve the codes that will tell you what is wrong. Second thing is does it ever blow out hot air? Perhaps your thermostat is shot. Third thing is what happened to my '96 Bonneville, though opposite (I get cold air that switches to hot very fast). It turns out that there is a little door down behind the dash (over the heater core) that switches around depending on whether you want cold air or hot. There is a small motor and small rod connected to this little door and your climate control tells the door to open or close depending on if you want cold or hot. If the door is not closing or opening properly then you will get hot or cold air or perhaps even warm.
Anyhow, check to see if the Temperature display flashes first and make sure you're car does warm up. That is a good start.
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Be aware that the Buick computer that controls these functions may be implicated and it an expensive part.. Runs in the neighborhood of $600 to replace, IIRC. It is not a part that you replace HOPING that it might cure the problem.
If you take the car to a dealership, be sure you discuss your problems, expectations, and LIMITS.
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Actually, I was not talking about the computer, I was meaning the rods and what not under the dash. Quite often they come loose or fall off thus giving you no heat, or no cold, or a combination of the two. Now, to fix the problem is quite the task, but it usually does not require parts, depending on what is wrong.
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Yes, I am aware of that, and understand how the system works. My comments were meant in addition to yours, not to supplant them.
If your vacuum system is not working properly, that mechanical system will not work either. But working with all that little crap under the dash can be a royal PITA.
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Especially if you have to remove the entire dash to get to the part(s) that need to be replaced.
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The temperature display does not flash, even though it has been very light for a year or so now, but I've learned to live with it as the whole climate 'thing' would have to be replaced for a lot of money and a lot of time direct with GM.
It does blow out hot air. Per below, if I wait about 5 minutes with the system off, then put it back to 90 degrees, it puts out hot air for about 20 seconds, then it turns cool again.
I'll have to take it to a dealership.
Thanks!
Michael
80 Knight wrote:

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Hmm, if you mean the climate control center (the one you press buttons on) then you could pick one up at a scrap yard for about $20, however, if you do indeed have a problem with it, like you said, then that could be causing your heating problems. That little box controls all the gizmo's and gadgets under your dash that provide heat or cold air.

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"Michael" wrote:
.... It does blow out hot air;if I wait about 5 minutes with the system off, then put it back to 90 degrees, it puts out hot air for about 20 seconds, then it turns cool again. ____________________________________________
I had an older car that did this. I discovered that the control valve for the heater water supply in the engine compartment was jammed almost closed.
With the heater fan off, enough water flowed to warm up the heater core and turning on the heater fan provided warm air for a short time, until it cooled down.
A new valve fixed it for me.
Good luck.
Rodan. ____________________________________________
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