Just got this truck, and trying to solve a recurring problem with the integrated trailer brake system. I get an error on the dash, Service Trailer Brake System. I've searched the internets and replaced the relay unit (mounted in the frame, by the spare tire) and just replaced the lower dash control unit with the slider bar and + and - buttons. The error remains, though sometimes it is intermittent. It happens with no trailer connected to the system, and with my trailer plugged in.
What else is there in the system that I'm missing? Other than these two parts, the internet wisdom on this seems to be lacking. I can't locate whatever fuse/s are supposed to control this system, and the wiring is all in a wrapped bundle. I sprayed the connector in the bumper with electrical contact cleaner and blew it out, no help.
Thoughts?
My mother had a 2010 Denali with the built in trailer brake controller and her boat trailer kept causing that error to pop up. I replaced that module by the spare tire as well and it didn't fix it. So I dropped it off at the dealership (at the time, I worked for the company that owned that dealer so I paid employee cost on labor/parts) and they replaced one of the big fuses at the main block under the hood. Poof. Never had the issue again. Don't know how the a fuse could be intermittent though.
iansane said:
My mother had a 2010 Denali with the built in trailer brake controller and her boat trailer kept causing that error to pop up. I replaced that module by the spare tire as well and it didn't fix it. So I dropped it off at the dealership (at the time, I worked for the company that owned that dealer so I paid employee cost on labor/parts) and they replaced one of the big fuses at the main block under the hood. Poof. Never had the issue again. Don't know how the a fuse could be intermittent though.
I'd read something about such a fuse, but looked in the underhood fuse block and could not locate it. Any idea which fuse it is?
IIRC, it was bolted in like a PAL,Jcase, Mcase fuse. I want to say it was underneath the fuseblock? I didn't see it directly, just a generic hand waving when the tech was telling me what he did.
Pulled out the #68 fuse, the cover said it controlled the aux power out, which I believe is for the trailer brake. Cleaned the fuse contacts, cleaned the contacts in the underhood fuse box, checked continuity across the fuse with a meter, put it all back together, cleaned and checked some other fuses for trailer-related stuff. Now with the trailer connected, when I turn the truck on, I get a "Trailer Connected" message, and no more errors. Huzzah! Hope this fixes it. Thanks for the suggestions!
EDIT: the #68 was for my truck with the gas engine. It looked like the diesel would have been a different #, there were 2 schematics on the inside lid of the underhood fuse box.
I realize this means no more BST. I'm a little sad, because I really liked BST. But I also really liked the D250.
It'll be really nice towing your trailer with the new truck though, I'm sure. GMT900s are really nice. So much quieter than even the GMT800s.
In reply to buzzboy :
Yes, I was a bit sad sending the BST down the road. On the plus side, I got five years worth of use out of it, and sold it for twice what I paid for it.
The new truck is pretty nice. It's a work truck, vinyl seats, crank windows, rubber floor mats. Just a 6 liter gasser with a 6 speed automatic, an 8 foot bed, 4 full-size doors, and four-wheel-drive with the selector on the floor as a lever, as God intended.
I still consider the d250 the best truck I've ever owned, but man the new trucks are so much more refined.
Went to pull out of the driveway Saturday morning and the stupid trailer brake error popped back up again.
Ugh.
In reply to volvoclearinghouse :
I know nothing about your truck or controller, but have you cleaned every ground connection you can find? That's seemed to resolve most trailer wiring issues I've encountered.
Pete Gossett (Forum Supporter) said:
In reply to volvoclearinghouse :
I know nothing about your truck or controller, but have you cleaned every ground connection you can find? That's seemed to resolve most trailer wiring issues I've encountered.
I think that's the next step. Since it seems to happen with or without a trailer connected, the problem has to be on the truck side. Unfortunately, the wiring all disappears into a bundle, so I'm not sure where the ground points are.
I had just cleaned and checked the fuses before; I'm going to buy new ones today. Maybe there's a weak/ poor connection?
