How to replace blower motor resistor pack and connector pigtail

mitch

Original poster
Member
Feb 21, 2012
8
I lost my #5 fan speed yesterday while it was 85 degrees outside and could still hear the relay clicking when I switched from 4 to 5, so I figured it was time to start researching what the problem was. I learned a bunch from the old guard both here and on the old site, so I decided since this is a common problem and most likely will happen to everyone if they keep their truck long enough then there ought to be a resource available to people on the nation (visually at least) lots of how to's written in text.

photo12.jpg


Remove this panel below the glove box

photo8.jpg


when you contort yourself underneath the panel after you've removed it and unclipped those 4 harnesses from it (little grey plastic retainers, I just ripped them out) you'll see the gold screws holding the resistor pack in, I don't remember what size but grab your 6 point mini sockets and go to town... After you've dropped it down you'll have to remove the connector from the blower motor itself, to remove that you'll probably be contortioning yourself with a set of needle nose or a screwdriver and reaching underneath it from the floor board. This is what you'll see after it's all disconnected.

photo20.jpg


At this point you can either remove the connector from the resistor pack or it's melted in there from overheating and it won't come out to save your life and you need to just take the plunge and cut the wires off, but first I'd make sure you have a replacement set on hand. If you went to Autozone it'll look something like this.

photo19.jpg


New one on the left, old one I cut out with wire cutters on the right and a new connector pigtail assembly with wire crimps below it.

photo18.jpg


This is the pigtail with new connector plugged in so I can start the crimping process and then electrical tape wrap and feed it through. At this point you'll want to feed the wiring harness that you cut off the old resistor assembly through the now lowered glove box like this.

photo17.jpg


strip the wire ends so you can crimp them

photo7.jpg


Using the old connector as a guide, start with the wires on one end and just do a one for one swap. The new connector I got only had black and white wires on it, not the rainbow colors like the old one.

photo22.jpg


This doesn't matter though, just start with one side and work your way over using the old connector you cut off.

photo16.jpg


This is what it will look like when you're done, only thing left now is to plug everything back in and test it to make sure it works.

photo14.jpg


Everything worked on mine, all 5 fan speeds A-OK at this point. Now you'll want to wrap everything up neatly using some electrical tape to keep those wires from getting tugged out of their crimped position (they should be tight enough, but let's just assume they aren't and secure it anyway.)

photo13.jpg


Now we just need to make sure everything goes back in place properly and the resistor pack is plugged back into the blower motor and we can put our kick panel back on. Now it's time to see what caused this whole mess, I ripped my old connector that was firmly melted in place on the resistor pack off and broke a few pieces of plastic off to see what the hell happened.

photo10.jpg

photo9.jpg


This is what happened to mine, probably most people's A/C fan issues with the same symptoms are due to similar failures. If you intend to replace the resistor pack, then you should most likely replace the connector as well. I picked them both up from Autozone for about 28 US dollars a piece. Good luck to each of you.
 

chaffin14

Member
Aug 7, 2012
4
I'm replacing this in my 04 envoy now. My issue is my connector only has 3 wires instead of the 7 shown in your picture. Is that to mean I'm going to have to do a lot of wiring? I'm kinda new at all this but I need to get this fixed. Any help would be great.
 

JerryIrons

Member
Dec 20, 2011
434
This is a great write-up by the way, thanks very much for doing this. A couple of things that I would add:
If you are like me and like to test things out before putting it all back together, you need to realize that the giant green resistor gets very hot when it is being used, in fact it depends on the same air that it controls and is blowing by it to cool off. Kind of a strange design, and prone to going bad in gm vehicles. So you can test it, but only briefly...don't ask how I know :smile:

Also I think a better solution would be to solder the wires together instead of using the butt connectors. (and all of the parts you buy include butt connectors) And then heat shrink tubing over that. (I couldn't find mine so I used some good electrical tape) I had replaced my resistor within the last year, and then had my blower motor itself go bad, when I looked over the butt connectors I had used before they had "softened" up some and things were looser. Maybe that was caused by current overdraw by the motor going bad, who knows but this time I replaced all 3 items, and soldered them together.

Lastly in response to the last poster the 3 wire prong I believe is for the automatic climate control. This one described in this article is for the manual one. Either way I think the procedure is fairly similar.

-Jerry
 

Cdrum

Member
Dec 4, 2011
30
We lost fan speed five, so I figured it was the blower motor resistor. Ordered one from Amazon, and replaced according these very good directions. Fan speed 5 still not working...5 seconds of fiddling with the speed selector switch, bingo fan speed 5 starts working! Lesson learned, don't assume its the resistor; work the switch over a few times before replacing the resistor :smile:
 

Ghost

Member
Jun 1, 2012
932
I just pulled my dash apart and pulled the resistor pack here's a picture and it doesn't look like what's in the photos and it looks good.

OK tapatalk keeps crashing don't have time to horse around. So what now ???? Nothing is fried or burned along the wireharness
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Ghost said:
So what now ????
First off, you slow down, catch your breath, and tell us your specific symptoms. Don't panic. It's just a blower control. What speed(s) are dead. What did your voltmeter tell you when you applied it to the wires? Do you have a voltmeter and the schematic to properly troubleshoot it without guessing or shotgunning?
 

Ghost

Member
Jun 1, 2012
932
yda9yguq.jpg
 

Ghost

Member
Jun 1, 2012
932
the roadie said:
First off, you slow down, catch your breath, and tell us your specific symptoms. Don't panic. It's just a blower control. What speed(s) are dead. What did your voltmeter tell you when you applied it to the wires? Do you have a voltmeter and the schematic to properly troubleshoot it without guessing or shotgunning?

Since I broke the control unit trying to take apart the switches got to replace that and get this too


http://pages.ebay.com/motors/link/?nav=item.view&id=320969498036
 

tmm217

Member
Oct 18, 2012
44
Alright have gone through almost 2 resistors. My ? is does a bad blower motor cause this terminal G and E to melt. I have no speed 5 and I metered power (bat voltage) to blower connector on all 5 settings. This does mean my resistor pack is still good right? Thanks for help in advance.
 

silverunicorn

Member
Dec 4, 2011
327
Thanks for the write up

I will be doing this tomorrow (I Hope)

I lost all speeds on the fan except for #5. I knwo how the Roadie is about shotgunning parts without metering stuff, but I honestly dont have the right equipment en expertise to do so.

I am hoping this will solve my issue. Will report back once I am done.

Chris
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
silverunicorn said:
... knwo how the Roadie is about shotgunning parts without metering stuff, but I honestly dont have the right equipment en expertise to do so....
Four year electrical engineering degrees aren't *that* expensive....:wink:

Seriously, it takes some experience with schematics to even learn what the nomenclature and shorthand is for each vehicle. The styles of the tech writing staff vary widely from mfr to mfr. Sometimes, it makes sense to shotgun, in this case because even if you knew what sub-component of the resistor pack was bad, you'd still have to replace it as an assembly unless you're really in a frugal and desperate need to save $25.
 

Ghost

Member
Jun 1, 2012
932
the roadie said:
Four year electrical engineering degrees aren't *that* expensive....:wink:

Seriously, it takes some experience with schematics to even learn what the nomenclature and shorthand is for each vehicle. The styles of the tech writing staff vary widely from mfr to mfr. Sometimes, it makes sense to shotgun, in this case because even if you knew what sub-component of the resistor pack was bad, you'd still have to replace it as an assembly unless you're really in a frugal and desperate need to save $25.

I took two years of DC and circuit design. Thing is I'm a procrastinating cracka. BTW parts have been replaced and it works great. I went with ACDelco parts, it cost a little more but was worth it.
 

triz

Member
Apr 22, 2013
746
I this as well but I have the automatic controls. I got lucky and found a LTZ with Auto and got the blower resistor off that. New aftermarket was 100 bucks Factory was well you can guess. Used was waaaaaaaay cheaper.
 

silverunicorn

Member
Dec 4, 2011
327
Mitch -

Thank you for this write up!!!! I did this repsir today and it worked great!

I was lucky in that my connector was completely fine. In fact, it looked brand new. No melting of the connection at all.

For reference, the bolts holding the pack in are 6mm (or at least that socked worked fine for me)
I also found it easier to remove the smaller plug if I removed thre glove compartment completely (3 6mm bolts is all that holds it on)

Here are pics of my old resistor pack - Gee, I wonder why it didn't work.....

11091025214_24f1b9e73c.jpg


11091014516_4b7da6af78.jpg



Thank you again Mitch!!!

Chris
 

miron

Member
Dec 29, 2011
56
Just as with several of the examples above, my connector is fried as well. I have replaced the resistor several times with the end result, #4 and #5 eventually quit. And it is due to overheating. I am curious if there is a way to increase the airflow across the resistor or if there is and obstruction, like maybe an inline filter element, cause the overheating. Regardless, I have my generic white/black wired connector from GM Parts East and a new resistor. So now I just need to contort my 6'2" 240lb frame into position to get the job done. I intend to solder and shrink wrap the connections and when done take a couple of Naproxen to ease the pain. Also, you don't need a degree to read schematics. 26 years in the Submarine Service as a logistician with techs that COULDN'T read schematics taught me quite a bit. Usually I can breeze through them no problem... usually.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
One possible root cause we've speculated is aging blower motors with deteriorating bearings causes higher current through the resistors and connector. After the second resistor replacement, I'd recommend a new blower.
 

SirRobin53

Member
Apr 27, 2014
118
:iagree: Also,the motors have brushes that grind their way into the armature and then semi short causing a MASSIVE load draw. I wonder if a brushless motor would be in order?
 
Feb 16, 2012
202
So I did the resistor replacement this past winter, and it worked great for about 6 months before I lost speed #4 again. I had not replaced the plugs or contacts. It was SUCH a PITA to do, I really do not want to have to go through it all again (although this guide was a big help in doing it).
 

Ghost

Member
Jun 1, 2012
932

Trkdrvremt

Member
Oct 22, 2014
351
NJ
Thats what I found... Haven't learned to solder yet... But I replaced it with butt connectors and made it neater...
 

Mounce

Member
Mar 29, 2014
13,667
Tuscaloosa, AL
Soldering wires isn't hard if you practice a couple times, good thing to learn. Soldering irons and heat shrink tubing are cheap too, try it out sometime. :yes:
 

Mark20

Member
Dec 6, 2011
1,630
My blower fan just gave up the ghost in settings 1-4. Of course the first thing to do is check here. Now I'll need to wait until my daughter brings the Voy back home this evening to take a look at the resister pack.
 
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gpking

Member
Dec 27, 2013
534
Berkeley Springs, WV
Mark20 said:
My blower fan just gave up the ghost in settings 1-4. Of course the first thing to do is check here. Now I'll need to wait until my daughter brings the Voy back home this evening to take a look at the resister pack.
I had the same thing happen last week.
I replaced mine with CarQuest brand, part # RU1070 and it was directly plug and play (I had no melted wiring or anything). Less than $30 all said and done.

If only all other electrical problems were as easy to diagnose and fix...
http://shop.advanceautoparts.com/p/carquest-by-bwd-hvac-blower-motor-resistor-ru1070/20974354-P
 

Mark20

Member
Dec 6, 2011
1,630
Pulled it this AM and though I didn't grab a pic, it looks just like the rusted one above. Green ceramic (or whatever) is cracked but wires are fine. I'll run to the store sometime this weekend and grab a new one.
 

Mark20

Member
Dec 6, 2011
1,630
Got a Duralast replacement at Auto Zone for $30. Went back in faster than it came out and all the fan settings are working again. I wish all the fixes were as easy as this one.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
Just wanted to say thanks for the info since I have been without 5 for awhile and now 1-4 only work if i play with the dial enough and get lucky. Hopefully I can findd the parts on Amazon today and get them on their way.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
Ok. Got new resistor in and worked for two trips and now I have no fan at all.

Should I be looking at blower or switch next? Kinda think switch since it was getting flaky before resistor and now does nothing, but the blower could have died I guess
 

Mooseman

Moderator
Dec 4, 2011
25,343
Ottawa, ON
Test at the fan connector for voltage with a test light so you should see increasing/decreasing light output.
 

HARDTRAILZ

Moderator
Nov 18, 2011
49,665
Thought about that a lil bit ago. Sucks cause it got cold and garage has couch in it right now. Just have to suit up and go after it tomorrow I hope.
 

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