Furnace blower won't stop running

This weekend I realized my furnace fan was running non-stop. My first thought was that we'd left the blower switch on, as we frequently do to keep air circulating in the house. But the blower switch was off, and even turning the HEAT/AC switch to OFF still left the blower running.
Is my thermostat finally toast? Is there a relay somewhere on the furnace that controls the blower that might be stuck? Or is it the electronic furnace control module? Or something else. How do I tell what is bad?
The thermostat is a programmable White 5/2 day 4 setting electronic.
The furnace is a Heil/Tempstar 100K BTU upright condensation furnace, about 15 years old. This fall the blower was replaced after it died.
NOTE: I would recommend everyone *** AVOID *** Heil Tempstar like the plague. The stainless steel heat exchanger rusted out prematurely, about 3-5 years IIRC. It was repaired by a local service person, but he told me there had been a safety recall on this unit. No notice was ever sent out in spite of having "registered" the warranty. When I contacted the manufacturer, they confirmed the recall, but wouldn't pay for the repairs. They had a "secret" recall that had "expired" before mine finally failed. It seems they would rather kill their unsuspecting customers than have to pay for warranty repairs. There have been at least 2 other design defect failures that I've ahd to eat since then. This is *** NOT *** a company you want to do business with.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
People who exercise their embryonic freedom day after day, little by little, expand that freedom. People who do not will find that it withers until they are literally "being lived." They are acting out scripts written by parents, associates, and society. --Stephen R. Covey
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Since we can't accurately diagnosis it over an internet connection, I'd suggest getting a licensed, insured technician out there to look at it.
Betcha it's a limit....

keep
about
3-5
there
spite
they
"secret"
business
http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf
www.nar.org
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On Sun, 2 Jan 2005 10:44:57 -0500, "HeatMan"

"My 24 volts. Who stole them....?" Bubba

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This is Turtle.
Bob , You just said to not buy any of these brands of hvac equipment for all are the same company now.
Carrier Bryant Hiel Whirlpool Tempstar Arco Aire and a host of other brand names
With this you can only buy 5 other brands out there Trane, Lennox, Goodman, Rheem, and York. Now the other may do better on this application.
On your problem. I can't see it from here but it sounds like a Fan relay in the relay board stuck. You can hit it with a hammer to see.
TURTLE
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writes:

Well, unless I get a response from Heil/Tempstar, that is what I intend to do. I certainly don't reward companies who don't stand behind their products with repeat business.

That looks like a sufficient list to pick from. Lennox was probably at the top of my list already. I've had zero problems with their central AC unit in the same 15 years.

I'll give that a try.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
Timid men prefer the calm of despotism to the boisterous sea of liberty. -- Thomas Jefferson
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On 2 Jan 2005 18:04:52 -0600, kaplow snipped-for-privacy@encompasserve.org.TRABoD (Bob Kaplow) wrote:

Lennox? You probably deserve them. Bubba

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writes:

This is Turtle.
Bob , Awwwww Lennox is not on my list of HIGH quality stuff but if installed correctly. It will be good but it will not cover the trouble that comes with a poor installation. If you can try to pick from the other brands in your area maybe. Now if the installer is a real good one it would tend to be OK stuff.
Just a Light warning here.
TURTLE
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