Blower motor fan speeds not working correctly?

Tiny
DAVID TOWNSEND2
  • MEMBER
  • 2006 CHEVROLET SILVERADO
  • 6.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
5 high speed quit working about a month ago, now fourth has quit. So I read up and replaced the resistor and wiring harness, and the 1-4 works fine but still no fifth. Read up and checked and changed the 40 fuse under hood, then fifth worked but not 1-4. Unplugged the fuse all together and 1-4 work and no 5, rep lug in fuse and only fifth works? Any help would be appreciated!
Friday, October 11th, 2019 AT 10:50 AM

35 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good afternoon,

I attached a diagram for you to view.

The blower switch provides power to the blower resistor in 1-4. 5 is a direct bypass from the blower switch to the resistor and to the blower motor.

What brand resistor did you use?

Roy
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Wednesday, April 28th, 2021 AT 12:22 PM
Tiny
DAVID TOWNSEND2
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Duralast, from AutoZone.
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Wednesday, April 28th, 2021 AT 12:22 PM
Tiny
ASEMASTER6371
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What harness did you replace?

Roy
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Wednesday, April 28th, 2021 AT 12:22 PM
Tiny
DAVID TOWNSEND2
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The 6 wire junction box.
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Wednesday, April 28th, 2021 AT 12:22 PM
Tiny
DAVID TOWNSEND2
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A couple of the terminals looked as if they had gotten a little hot.
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Wednesday, April 28th, 2021 AT 12:22 PM
Tiny
ASEMASTER6371
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Okay, are you sure you put the wires in the correct location on the pigtail?

I would also get a GM resistor as well. Some of the aftermarkets do not meet the quality standards of the original.

Roy
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Wednesday, April 28th, 2021 AT 12:22 PM
Tiny
CLB1061
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  • V8
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My Heater / Air Conditioning blower doesn't work on the High (or #5) Setting. It works on all of the other setting, 1 thru 4, but not 5.
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Friday, April 30th, 2021 AT 3:23 PM (Merged)
Tiny
OBXAUTOMEDIC
  • MECHANIC
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Sounds like the Blower Motor Resistor. It is located in the duct work under the passenger dash.

Looks like this...


https://www.2carpros.com/forum/automotive_pictures/188069_05silverodo_1.jpg

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Friday, April 30th, 2021 AT 3:23 PM (Merged)
Tiny
FUG
  • MEMBER
  • 2 POSTS
  • 2003 CHEVROLET SILVERADO
The heater fan only works in the high position. I have heat, but when I dial the setting knob to 1, 2, 3 or 4 there is no heat blowing through the vents. Where should I start to fix this issue?
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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Locate the blower motor resistor it controls the blower motor speed through resistances. The lower the number the slower the blower will blow.
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
FUG
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What do I do when I find the resistor?
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
RASMATAZ
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Replace it.


https://www.2carpros.com/forum/automotive_pictures/12900_blower_resistor_11.jpg

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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
PTT2004
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When I switch from floor to upper to dual vents, that seems to work. Air conditioner doesn't blow cold air but the light for the A/C button is on and lit. Not sure if related but in September 2018, a flood hit our block and water was up to the floor of the cab. I had a company remove carpet and clean/dry carpet. I've never done anything to the A/C system since purchase. Thanks. Brian T.
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
DANNY L
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Hello, I'm Danny.

Quick question first. Was the interior submerged with water? If not a common problem with these trucks are the blower motor resistor. It's mounted on the HVAC box next to the blower motor. I've attached a picture below of its location (#5). They have had a problem melting/poor connection/loose wires. Hope this helps and thanks for using 2CarPros.
Danny-
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
JIM3675885
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  • V8
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My heater / air conditioner fan blower is NOT working on positions #1, 2 & 5. It does work on positions #3 & 4. What do I need to do to repair this?
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
GFIMOTORCARS
  • MECHANIC
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The problem you are descibing is a failed blower motor resistor. This is located under the passanger side dash next to the blower motor. It is a pretty easy fix. Couple of screws and one connector. Note the connector goes to the blower motor for location identification.
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
BEAU2007
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The ac/heating swich does not work from 1-3 but 4 and 5 work how do I make 1, 2, 3 to blow air?
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
PASTORKEV316
  • MEMBER
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I had this on my 1997 GMC Sierra. Remove your Glove box and look on top of your black blower box. You should see wires plugged in. Remove the wires and the two screws on either side of plug and remove the module. This part costs about $13 to replace but fixed the problem for me. SOrry not sure what to call it. (Blower Speed Control Module)
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
YAHOO4
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Blower motor resistor, yours is on the bottom pass side where your toes would be
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Friday, April 30th, 2021 AT 3:24 PM (Merged)
Tiny
RJOU319
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  • V8
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The blower for the heating/air conditioning fan does not work on speeds 1 and 2. It only works on settings 3, 4 and 5. I've pulled the switch and checked the wiring hraness and haven't found any obvious cause. Should I buy a new switch and hope that solves the problem? Thank you for the prompt replies. I could check the voltage if I had a clue how to go about it, but I must admit that isn't something I'm familiar with. A co-worker suggested the resistor as well, however, I'm having trouble locating it. Any help with either of these dilemmas would be appreciated.
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Friday, April 30th, 2021 AT 3:24 PM (Merged)

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