gmc canyon repair, fixing the crappy ground

I mentioned before (which does list the parts) the issue on GMC Canyon/Chevrolet Colorado trucks where the HVAC fans completely stop working for no reason while running. Today I fixed it myself at my father's place because he had the tools I needed. The job took about a half-hour to complete.

The fix for the buggy HVAC fans in a Canyon is to fix the ground connection, which is oh-so crappy from the factory. This not only improves the connection but also prevents the blower resistor from failing again, again and again.

Short description of fix:

1. Remove bolt from passenger side fender under the hood holding splice pack.
2. Sand off paint where the splice pack strap met the fender.
3. Sand off coating on splice pack strap where strap met the fender.
4. Sand off coating on splice pack strap where bolt washer meets strap.
5. Reattach, seal.

Long description of fix:

The splice pack is a small black box directly to the left of the air filter. You need to remove the air filter cover and air filter itself in order to get to it, so the first thing I did was pop off the three clips holding the air filter cover, removed cover, put to the side, then removed the air filter so I could get easy access to this little box bolted into the fender.

The bolt is a 10mm, so I used a ratchet to remove that.

After that I decided to tackle removing the coating off the strap first. The bolt thread side was easy. I used a very small cone-shaped sand drum on a Dremel and sanded that down until it was shiny.

The other side however was a pain in the ass. Since the bolt will NOT come out of the strap no matter what you do, and the fact there's a bolt washer there, I had to manually sand that by folding some sandpaper, wedge it between the bolt washer and strap and sand that down as best I could.

Once that was completed I sanded off a ring of paint surrounding the hole where the bolt goes. This was the easiest part of the job.

The bolt was then reattached, and I used some RTV silicone sealant to seal it up so it wouldn't rust. To help me out I used a small modelers brush to get into the tight spots.

The directions on the sealant said to let it cure for at least 30 minutes, so I left the hood open for that long to let the sealant do its thing. After that I shut the hood and it was a done deal.

Result of fix:

The first obvious thing was that the chirping noise the blower motor made at low speeds decreased significantly, almost to the point where I no longer hear it. This strongly indicates that that motor may have been arcing ever so slightly when it was in use with the original crappy ground.

The second thing I noticed is that my A/C now blows colder. Nice side effect, especially in Florida.

The third is that the truck is much more "civilized" when driving her. She seems a lot more tame in a real good way. From acceleration curve to highway manners and just about everything in between, she's just an all around better driver now. Maybe it's all in my head, but it was something I noticed. On the highway in particular, I thought, "Wait a sec.. she's driving a lot more smoothly..?" Yeah, she was.

Does fixing a crappy ground connection really make that much of a difference? Evidently it does.

Published 2010 May 1