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Blower motor not working

Tiny
NATHANHANOVER
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 225,000 MILES
SUV listed above two door with a 4l60e transmission.
Two years ago put on all new A/C under the hood and new climate control module in the dash. With in a year the high fan control setting stopped working. I waited until now to resolve it as I was going to change the engine.
So I replaced the dash environment control module switch. I replaced the A/C box resistor. Tried the unit still not running on high.
I then replaced the Fuse box relay and the relay that sits beside the resister under the dash. Still does not run on high switch setting.
I spoke to several mechanics they said there is a fuse in the fuse box under the hood that powers the high setting. Turns out inside the lid there is a listing for a fuse but this SUV simply does not have that fuse equipped in there. Not sure if they changed the set up from 1998 and a half through 1999 and a half but that is what I am looking at. The vehicle is stock.
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Saturday, May 11th, 2019 AT 11:25 AM

33 Replies

Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello, I'm Danny.

There is a blower motor relay for the 'high' setting. Have you checked/replaced? Here is a tutorial on how to test:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

It's attached to the HVAC unit under the dash and I've attached a picture below of its location (#11). Hope this helps and thanks for using 2CarPros.
Danny-
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Saturday, May 11th, 2019 AT 6:14 PM
Tiny
NATHANHANOVER
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  • 23 POSTS
Danny: I explained that I just put in new relays among other new parts. Did you bother to read the info?
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Monday, May 13th, 2019 AT 1:08 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,512 POSTS
Sorry for the misunderstanding. Lets test for power at the blower fuse #3. here is the fuse location and and guide to help you test with the blower motor wiring below so you can see how the system works:

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

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Monday, May 13th, 2019 AT 1:13 PM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
Hello, my fuses are fine checked them, but my fuse block isn't set up in this manner.
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Monday, May 13th, 2019 AT 1:25 PM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
Hello, I explained that I changed both the fuse box relay, and the relay that bolts next to the resister with the glove box out. So when switching from 3 power to 4 power you can hear the relay click that is new but the fan shuts off instead of speed 4. Or max speed. Maybe the new relay is defective or bad?
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Monday, May 13th, 2019 AT 1:32 PM
Tiny
KEN L
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  • 47,512 POSTS
Do you have power at the red wire at the high speed relay?
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Monday, May 13th, 2019 AT 1:39 PM
Tiny
NATHANHANOVER
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Do I test the wire with the relay in our out?
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Monday, May 13th, 2019 AT 2:40 PM
Tiny
NATHANHANOVER
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  • 23 POSTS
I don't have a voltmeter here at the moment its gone missing I tried a led light and tested it. No light. The relay in the fuse box clearly runs the compressor. So that one is ok. The fuse in the side panel of the dash has power cause I shorted it testing yesterday and replaced it.
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Monday, May 13th, 2019 AT 2:48 PM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
Okay, I went to the store and got a new one. If I put the probes on the red and orange wire only I get 25 v. But it won't respond on any other colors, black purple, and dark blue. This is with the switch on high and the relay plugged in.
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Monday, May 13th, 2019 AT 4:50 PM
Tiny
KEN L
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Can you unplug the high speed relay and jump the red with the purple wire on the connector with the key on to see if the blower runs?
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Tuesday, May 14th, 2019 AT 9:53 AM
Tiny
NATHANHANOVER
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  • 23 POSTS
Good morning Ken. I can later today I am at the VA this am. Thank you thus far for all your help!
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Tuesday, May 14th, 2019 AT 11:31 AM
Tiny
KEN L
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Okay sounds good, let us know.
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Wednesday, May 15th, 2019 AT 9:42 AM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
Ken: When I try to jump the red to purple wire nothing happens. I had just put in a new switch inside the control module. I can only assume the new switch is defective?
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Saturday, May 18th, 2019 AT 7:19 PM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
I purchased yet another fan motor switch, Standard brand HS246 and the high power still does not come on. This is simply crazy.
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Sunday, May 19th, 2019 AT 3:23 PM
Tiny
KEN L
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Do you have power at the red wire? Use a test light to see.
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Monday, May 20th, 2019 AT 10:57 AM
Tiny
NATHANHANOVER
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  • 23 POSTS
Voltmeter shows 25 at the wire.
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Monday, May 20th, 2019 AT 11:33 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
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25 volts? The system has 12? Can you use a test light and if it lights up you have power the fan should run if not check the ground.
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Monday, May 20th, 2019 AT 11:36 AM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
I already put a new addi Onal ground wire on that bundles black wire and the fan Black wire t-ed to the oem dash ground stud. I don't own a test light will have to buy one.
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Monday, May 20th, 2019 AT 11:46 AM
Tiny
NATHANHANOVER
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Amps.
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Monday, May 20th, 2019 AT 1:00 PM
Tiny
NATHANHANOVER
  • MEMBER
  • 23 POSTS
Ken. Relay model out key on switch on high no power to red. Orange wire only light comes on.
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Monday, May 20th, 2019 AT 3:31 PM

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