Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Lezperado

TYF Newbie
Joined
Feb 5, 2026
Posts
12
Reaction score
18
Vehicle information: 2015 GMC Yukon XL SLT 4WD

Good morning all,

I'm having some strange issues with my 2015 XL SLT that I'm trying to see if anyone else has experienced. The issue that I'm experiencing is both an intermittent right headlight failure warning and an intermittent windshield wiper failure (inoperable).

I would like to start with the headlight issue: when the warning light comes on, the interior signal indicator blinks fast, however, when you go outside both lights in the front and rear are operating as normal. This problem seemingly only occurs below 32 degrees Fahrenheit and when driving in the snow/ice. The warning light will go out and be fine for days and even weeks and then come back. This originally led me to believe that there was an issue in the wiring because when this happened it also affected the mirror turn signal.

Secondly, about a week or so after this started, I got into my vehicle and my windshield wipers wouldn't work. I took it to a trusted family mechanic, as I didn't have time to fiddle with it, and he changed the windshield wiper assembly. We came to that conclusion after the mechanic hooked up his computer to override the turn signal and wiper control stalk and he also couldn't operate the wipers. We were both under the impression that this was the issue. I got back into the vehicle following the assembly replacement and the wipers didn't work. We checked the part and the dealership we purchased it from and it was not the assembly. I ended up needed to drive the truck and upon driving it the wipers started working again but went back out again
1f611.png
This issue ALSO only happens when the temperatures drop below 25 degrees Fahrenheit it seems.

This is where I'm at now and why I'm hoping for some advice/second opinion. The mechanic believes that my fuse box is faulty, however, when we took the fuse box out there is no corrosion. We looked up the wiring schematics and it turns out that GM unfortunately hard wired the wiper relay into the board that's on the fuse box and they are known to go bad but there's no way to really see if it is bad. The only solution is to replace the fuse box itself but the part new is $500 and once the box is opened (if it turns out to not be the fuse box) the parts store/dealership will not let us return it.

Has anyone else had this issue before? Are we looking in the right spot? I apologize for the lengthy post but if I don't have to spend $500 on this fuse box I really don't want to. Used was also not an option due to not being able to find a tested unit and additionally when finding a tested unit it was also not able to be returned. Thank you for reading this and for any advice that can be provided.

TLDR; intermittent wiper and right turn signal inoperability issue. Mechanic believes issue is $500 fuse box but we can't prove it. Wanting second opinion from masses.


IMG_7420.jpeg
 
OP
OP
Lezperado

Lezperado

TYF Newbie
Joined
Feb 5, 2026
Posts
12
Reaction score
18
Check for any water intrusion by the fuse boxes. It kind of sounds like the BCM is either going bad or has loose connections. Did you check the ground wires? It’ll cause these issues too
It definitely does. The BCM, is that in the fuse box or separate unit? I’m new to repairs so I apologize if that’s a stupid question. Haven’t yet checked ground wires.
 
OP
OP
Lezperado

Lezperado

TYF Newbie
Joined
Feb 5, 2026
Posts
12
Reaction score
18
Check for any water intrusion by the fuse boxes. It kind of sounds like the BCM is either going bad or has loose connections. Did you check the ground wires? It’ll cause these issues too
Btw cute bulldog if it’s yours! I also have one
IMG_4211.jpeg
 

Joseph Garcia

Elite Member
Supporting Member
Joined
Aug 2, 2018
Posts
10,514
Reaction score
15,259
Btw cute bulldog if it’s yours! I also have one View attachment 477683
We have a Thread where members post photos of their dogs. I suggest that you post a photo or 2 there. @Fless can give you a link.

The BCM (Body Control Module) is a separate module about the size of a paperback book, and it is located under the dash between the driver's legs. When you look at it in its location, it will have about 6 multiwire plugs attached to it.

You said that your mechanic put a computer on the truck, and I am assuming that you are referring to a bi-directional scanner. What trouble codes did he see when he hooked up the scanner?
 

Fless

Staff member
Moderator
Joined
Apr 2, 2017
Posts
16,612
Reaction score
34,385
Location
People's Republic of Colorado
We have a Thread where members post photos of their dogs. I suggest that you post a photo or 2 there. @Fless can give you a link.

 
OP
OP
Lezperado

Lezperado

TYF Newbie
Joined
Feb 5, 2026
Posts
12
Reaction score
18
We have a Thread where members post photos of their dogs. I suggest that you post a photo or 2 there. @Fless can give you a link.

The BCM (Body Control Module) is a separate module about the size of a paperback book, and it is located under the dash between the driver's legs. When you look at it in its location, it will have about 6 multiwire plugs attached to it.

You said that your mechanic put a computer on the truck, and I am assuming that you are referring to a bi-directional scanner. What trouble codes did he see when he hooked up the scanner?
I will absolutely do that, thank you.

Okay sounds good.

It was a bi-directional scanner and no codes came up which is why we are stumped.
 
OP
OP
Lezperado

Lezperado

TYF Newbie
Joined
Feb 5, 2026
Posts
12
Reaction score
18
But will the scanner read body codes? My suggestion would be to scan it while the warning light is showing.
No warning light shows for the wipers and every time the light doesn't work and the warning light comes on, it goes off as soon as we attach the scanner, the light starts working and the warning light goes off. I can't even make this up if I tried.
 
OP
OP
Lezperado

Lezperado

TYF Newbie
Joined
Feb 5, 2026
Posts
12
Reaction score
18
SOLVED!!! There was a wire going in to the harness, after where the assembly plugs into, under all of the plastic that melted. Apparently when the assembly itself went, it back fed power and melted wires.
 

Forum statistics

Threads
138,035
Posts
1,997,525
Members
102,972
Latest member
mudrunnerz
Back
Top