Fan won't shut off

LORIDEMANN

MEMBER
2004 CHEVROLET TRAILBLAZER
6 CYL
4WD
AUTOMATIC
181,000 MILES

The AC/Heater fan won't shut off after vehicle is shut off, 2004 chevy trailblazer, any ideas on what is wrong? We had to disconnect the battery to get the fan to stop running.

Saturday, July 30th, 2011 AT 4:38 AM

6 Replies

LORIDEMANN

MEMBER
2 POSTS

Thanks guys, it's done and it works. Any ideas of why we go through these so often though? Replaced very same part less than 3 years ago and this part was heat damaged. You could smell the burnt smell on the actual old part after we removed it. Man, you guys are awesome!

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Saturday, July 30th, 2011 AT 9:00 PM

KASEKENNY

MECHANIC
18,907 POSTS

More than likely this is a relay that is sticking on, or the control module has shorted.

Basically, the way we need to test this is to go the control module which is under the dash and test if you have voltage coming in and out that is 12 volts even when the key is off. If it is, then this is shorted.

Here are a couple of guides that will help with this:

https://www.2carpros.com/articles/how-to-check-wiring

I am attaching the info below on this, but I suspect the module is the problem.

Please let me know what questions you have.

Thanks

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Monday, March 7th, 2022 AT 4:46 PM

LORIDEMANN

MEMBER
2 POSTS

Hi! We just came from O'reilles Auto parts, and they said it is the Blower Motor Resistor which we had replaced about 5 years ago and it is bad again, it seems. Can you tell me how to get info on replacing it? My husband will do it, watched the other mechanic do it the first time but can't remember how he got to the part to replace it? Ie. Through the dash but is it the glove box area or driver's side? How do you get to the part?

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Monday, March 7th, 2022 AT 4:46 PM

KASEKENNY

MECHANIC
18,907 POSTS

This is the control module that I attached the info on my previous post. Sorry but a resistor is just another name for it.

Thanks for the update and let us know what other info you need. Thanks

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Monday, March 7th, 2022 AT 4:49 PM

LORIDEMANN

MEMBER
2 POSTS

Thanks guys, it's done, and it works. Any ideas of why we go through these so often though? Replaced very same part less than 3 years ago and this part was heat damaged. You could smell the burnt smell on the actual old part after we removed it. Man, you guys are awesome!