The HVAC blower motor will not turn off?

Tiny
TRISTIN ANDEWAY
  • MEMBER
  • 2006 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 142,000 MILES
AC/heater blower fan won’t shut off after shutting off truck and keys out of the ignition. Started with having little to no heat and no control of fan speed. Every other setting seems to work. Just recently I replaced the blower motor resistor and connectors, now the fan runs on high all the time and still don’t have fan speed control. Checked all the fuses and tried resetting the HVAC control module with no luck. Any advice is greatly appreciated!
Tuesday, January 10th, 2023 AT 8:28 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
It sounds like you have a defective speed control resistor (module) because this is what happens when the resistor goes out. Also, I would check the ground circuit which this guide can help with.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Here are the blower motor wiring diagrams so you can see how the system works, the ground is located at the right pillar A. Check out the images (below). Let us know what happens and please upload pictures or videos of the problem.

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Wednesday, January 11th, 2023 AT 10:59 AM
Tiny
TRISTIN ANDEWAY
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I took out the module I replaced and switched it out for another one from O'Reilly's but still had the same problem. I had some trouble locating the ground circuit, even though I didn’t take too much time to look for it. Could it be the blower itself or possibly the climate control panel?
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Wednesday, January 18th, 2023 AT 7:40 PM
Tiny
KEN L
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I don't think the blower motor will cause that, but the HVAC controller might, here is how you can change it out in the diagrams below.
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Friday, January 20th, 2023 AT 9:18 AM

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