Trailer Brake Issue

UWSkier · August 3

There was a TSB on this last year. I had my truck fixed with that TSB at the time. When it was in for the transmission re-learn, they said the truck had a recall and ordered a part for it. Is it the same part again? My trailer brakes have been perfect since they performed the TSB.

BuckWallace · August 3

1 hour ago, UWSkier said:

There was a TSB on this last year. I had my truck fixed with that TSB at the time. When it was in for the transmission re-learn, they said the truck had a recall and ordered a part for it. Is it the same part again? My trailer brakes have been perfect since they performed the TSB.

I think there might be a new part. I took mine in at the end of May to get the TSB performed and the part they put in was a different number than the TSB called for. I was worried it was wrong, but I've been on two trips towing with my solar on and haven't had a single issue since. I wouldn't necessarily think you'd need the "new" part, but who knows if they can mark your recall as complete with the older part number.

Chadw90 · August 3

On 8/1/2024 at 11:50 PM, bruceb58 said:

You have the gain set the same?

Exact same

marpel · August 4

Okay, so I am really confused now, as it seems a couple different things are being discussed.

Chadw90,

In a couple of your posts, July 11, you discuss replacing the in-dash controller and "magically have brakes". However, a closely related trailer brake issue was introduced (re solar etc) and a tangent discussion developed (not complaining about that, at all). Then on Tuesday, you discussed taking your truck in for the module replacement and report that your amperage went up. Does this mean that replacing the in-dash controller did not solve the problem, or....?

I ask, because I have purchased the in-dash controller but have yet to pull apart the dash to replace it, and if it won't solve the problem, I am not sure I want to go through that procedure.

Or are you talking about something different??

Thanks,

Marv

Chadw90 · August 4

8 hours ago, marpel said:

Okay, so I am really confused now, as it seems a couple different things are being discussed.

Chadw90,

In a couple of your posts, July 11, you discuss replacing the in-dash controller and "magically have brakes". However, a closely related trailer brake issue was introduced (re solar etc) and a tangent discussion developed (not complaining about that, at all). Then on Tuesday, you discussed taking your truck in for the module replacement and report that your amperage went up. Does this mean that replacing the in-dash controller did not solve the problem, or....?

I ask, because I have purchased the in-dash controller but have yet to pull apart the dash to replace it, and if it won't solve the problem, I am not sure I want to go through that procedure.

Or are you talking about something different??

Thanks,

Marv

I replaced the gain switch/controller and my brakes started working fine again. Made a couple trips with two different trailers and then after the second trip, same thing again, no trailer brakes.
took my truck in and they replaced the module by the spare tire, and the gain switch again. The module was failing the gain switch.

marpel · August 5

Chadw90,

Thanks for the clarification.

I doubt the dealer will be replacing my module on their dime, as it does not have any related recall notice and they have already told me the system is adequate to their standards, so it appears I will have to pay (even though the truck is only two years old....). Any idea whether that replacement can be a DIY process, and cost? I presume I will not have to change out the harness, just the module (and I suppose I will not have to replace the controller as initially thought).

And any guess why your brakes appeared after installing the controller, then disappeared shortly thereafter?

Marv

Chadw90 · August 5

12 minutes ago, marpel said:

Chadw90,

Thanks for the clarification.

I doubt the dealer will be replacing my module on their dime, as it does not have any related recall notice and they have already told me the system is adequate to their standards, so it appears I will have to pay (even though the truck is only two years old....). Any idea whether that replacement can be a DIY process, and cost? I presume I will not have to change out the harness, just the module (and I suppose I will not have to replace the controller as initially thought).

And any guess why your brakes appeared after installing the controller, then disappeared shortly thereafter?

Marv

No idea Marv,

Just as I think everything is working properly, this $100K truck lets me down again. Hooked it up to a new camper tonight, leaving the lot, i grabbed the manual slider, BAM, brakes so hard and fast it would scare you.
Get out on the highway and a kite behind the trailer would create more drag than the brakes on gain 10 and manually engaged to 100%.
But with more fiddling around and paying extra attention, under 40km/hr, they work good. The faster you go the less effective they are. And I know before someone goes into the theory of inertia, i get it, but this is like you can hardly tell if the exhaust brake or trans braking is doing the work. I actually turned both off to try.
Now is there an issue with the pre 24’s and trailer battery back feeding once charged?
If GM designed the braking logic this way, the engineer must have fell on his noodle. This is 100% opposite to a new Ford if you’ve driven one, they dial back the braking at low speeds to accommodate for inertia and to prevent lockup at city speeds or around corners for those who like to run a higher gain.

Im not even sure what to do now other than trade out of this into a dodge or ford.
Like i told the dealer, 95% of people do a tug test when taking off and forget about it. Id like to talk to GM tech support directly because as per my resume, I understand the theory of electrical better than the techs working on these trucks at the dealers around here.
Any good tech from automotive in this area gets poached by companies like me or my competitors lol. Damn karma!

where are you from Marv? Canada I presume? I recall you referencing kilometres in a post. I will keep you updated as I dig further into this.

bruceb58 · August 5

If this was my truck, I would be running a wire up to the cab hooked up to a voltmeter so I could see what the voltage was while pulling the trailer.

Edited August 5 by bruceb58

Chadw90 · August 6

so i was in a mad panic today to leave to the lake. I pulled the battery posts off the trailer battery and the brakes worked 100% the whole 300kms trip. Not sure if its a coincidence. Maybe a diode on the charge circuit is needed?

22 hours ago, bruceb58 said:

bruceb58 · August 6

2 hours ago, Chadw90 said:

so i was in a mad panic today to leave to the lake. I pulled the battery posts off the trailer battery and the brakes worked 100% the whole 300kms trip. Not sure if its a coincidence. Maybe a diode on the charge circuit is needed?

What kind of trailer battery do you have? No solar charging right? No DC to DC converter from the truck to the trailer as well?

Chadw90 · August 6

Regular lead acid,no solar charger.

marpel · August 12

Chadw90,

Sorry for the delay, been a bit busy. Yes, I am from Canada (greater Vancouver, BC area).

However we are about to drive to Denver, Co in a couple weeks (we usually drive to/from here/there a few times a year) and after buying a new controller, I was going to install it and take the trailer (thinking it would solve the issue). However, now that you are still experiencing issues, even with a new controller and module, I don't think I will go to the trouble right now just to have the problem persist. It was a pain the last trip, having to manually activate the controller at every stop on a 5000 km trip.

Guess we will drive without the trailer and try a fix when we return.

Marv