2024 Brake controller Problems

lurker_007 · August 14, 2023

Just commenting to share my similar experience. I work at a Chevy store and I have a 2024 Siverado 3500 srw gas and a 2021 Coachmen 298RLS fifth wheel. I have towed this trailer with 5 different trucks and never had an issue. I got my new truck a few months ago and pulled my trailer from Savannah, Ga. to Ft Wilderness (Disney in Orlando) trip was flawless all the way there aside from a tire blowing out. The day we hooked up to come home I couldn't get the trailer brakes to work no matter if I plugged it into the bed or bumper. After trouble shooting for an hour we decided to just try to limp it home and drive slow. The manual override (factory brake controller wouldn't work) and there was no braking at the trailer axles. I figured out that the trailer brakes would randomly come on in full force after stepping on the brake pedal or 10 or more seconds... Which then as long as I squeezed the controller it would actually work. But as soon as I let off the controller or foot brake I would get the "check trailer connection" warning and no longer have brakes. So I adjusted my gain down and limped home allowing the brakes to kick on after 10-15 seconds of holding the brake pedal each time. We stopped in Daytona to fill up and shut the truck off for 30 mins or so and pretty much the truck worked normally for the remainder of the trip.

SInce then we have put another 1,200 miles on the truck and trailer and have learned to drive it cautiously. I have had my dealership look at my truck multiple times (at least 5) and they've made me ride around with a trailer simulator and a homemade brake magnet tester to trick the truck into thinking it had trailer brakes hooked up. It has never given a warning with either of their testers so they've informed me that gm says that it's my trailer, not the truck per GM tech line.

The issue is, this happens with my other bumper pull travel trailer as well. This trailer pulled fine behind all of my other trucks as well as my wife's 1500 and our Tahoe. But with my truck it gives me the "check trailer connection" and no brakes.

In the last few months I've talked my dealership into replacing the brake controller on my truck as well as the module up above the spare tire. I have also hacked into my new trailer wiring and put a new Pollak style connector per GM's request. None of it has made any difference. I also hooked up two other new 2500 HD trucks to my trailer and got no warning messages. I did this with a 2024 Custom which has the old interior and software as well as a 2024 LTZ that has the new interior like mine. Neither truck gave me a warning message.

Fast forward to today when I found this thread. Sure enough my vin has this TSB attached to it. Although I do not have solar or a generator it almost exactly describes what is happening to me. This morning I actually pulled my trailer to work as we were camping over the weekend. I towed the trailer about 30 miles to work this morning and had the warning message pop up at least 45 times.. I stopped counting. After letting the tech diagnose and plug his pc into the truck to record what was happening to no avail and him saying that gm is saying that it's my trailer again... I decided to google it some more and found this thread.

After brainstorming, I decided to disconnect my negative battery terminal on my trailer effectively stopping any possibilty of backfeeding. I then pulled it around about 6 miles and had no warning messages and the brakes worked flawlessly. I will pull it home tonight (about 15 miles) and see if I still have luck.

Only making this post as I do NOT have solar or run a generator while traveling. My truck does have the 220amp alt and the aux battery but I can't imagine that causing my battery to be overcharged in the trailer.

I understand that my breakaway cable wont work without the battery connected but I feel it is safer for me to have functioning brakes while towing until this is resolved.

I will update if anything changes.

Just wanted to share as this may be a bigger issue than just for those with solar or a generator.

Thanks

Edited August 14, 2023 by lurker_007

lurker_007 · August 15, 2023

Just updating to say that I pulled the trailer home last night with the battery disconnected and didn’t have a single warning light. This seems to have worked so far. I will look at possibly wiring in a diode on the trailer to prevent back feeding until GM releases a fix. This way I will still have a battery on the trailer and power to the brakes in the event of an emergency.

UWSkier · August 16, 2023

I actually had this issue yesterday with NO solar connected, NO generator running, nothing. Just pulling the trailer along when I got the "Check trailer wiring" message. I squeezed the manual brake slider and nada, for about 2 seconds, then full power with a "Trailer brakes connected" message. This was coming down the south slope of the Raton Pass in New Mexico so that was super fun.

I am an engineer and have sympathy for them generally, except when they're endangering my family. Not sure how this hasn't warranted a "Stop sale" from GM until repaired. I'd imagine the lawyers would hate the liability.

Edited August 16, 2023 by UWSkier

lurker_007 · August 16, 2023

9 minutes ago, UWSkier said:

I actually had this issue yesterday with NO solar connected, NO generator running, nothing. Just pulling the trailer along when I got the "Check trailer wiring" message. I squeezed the manual brake slider and nada, for about 2 seconds, then full power with a "Trailer brakes connected" message. This was coming down the south slope of the Raton Pass in New Mexico so that was super fun.

I am an engineer and have sympathy for them generally, except when they're endangering my family. Not sure how this hasn't warranted a "Stop sale" from GM until repaired. I'd imagine the lawyers would hate the liability.

This is probably my biggest concern. The technicians have told me that the truck monitors for a connection to the lights and brakes but they're separate circuits. When it thinks that the trailer doesn't have brakes, it doesn't send the braking signal to the trailer. So if there is ever an issue with your trailer wiring or trailer brakes, the truck will default to think that there is no reason to send a brake signal. This is DANGEROUS. Now with this new TSB it seems that the module actually shuts down all together.

Any other after market brake controller will always send the brake signal through the 7 way plug whether it has brakes or not. This is a much safer design.

Absolutley insane to me

Edited August 16, 2023 by lurker_007

NessGMC · August 20, 2023

Having the same issues with a 2024 GMC 2500 Denali Ultimate. I drove my trailer across the country with my old truck and had zero issues (2000 miles). Hooked it up to the new GMC and am getting intermittent periods where the trailer brakes are not working for the last 500 miles with the same errors as listed in this feed previously.

Anyone found other work arounds or have any insight if GMC has fixed the issue?

UWSkier · August 20, 2023

17 minutes ago, NessGMC said:

Having the same issues with a 2024 GMC 2500 Denali Ultimate. I drove my trailer across the country with my old truck and had zero issues (2000 miles). Hooked it up to the new GMC and am getting intermittent periods where the trailer brakes are not working for the last 500 miles with the same errors as listed in this feed previously.

Anyone found other work arounds or have any insight if GMC has fixed the issue?

I've ordered a diode I'm going to put into the 12v line so the trailer can't push any voltage back to the truck. Hope to do that, reconnect solar, then go for a drive to see if it fixed my problem.

BuckWallace · August 20, 2023

29 minutes ago, UWSkier said:

I've ordered a diode I'm going to put into the 12v line so the trailer can't push any voltage back to the truck. Hope to do that, reconnect solar, then go for a drive to see if it fixed my problem.

Let us know how that works out. Sucks we have to rig up stuff to make things work "properly", but having brakes is better than not having them...

madweazl · August 22, 2023

I have this issue pop up but not to the extreme it seems to be affecting other people. Our trailer is a '22 Cougar with the 400w solar package and dual 200ah lithiums so voltage is likely always over what the truck has. All the lights on our trailer are LEDs (interior and exterior). After multiple trips with the trailer, the only time I have this problem is when I hook up the trailer the night before and have it ready to go in the morning. After remote starting the vehicle, I'll get the disconnect message along with the trailer brakes disabled a few seconds and taking off and they wont work until I get to the end of my street (couple hundreds feet). I'm guessing the brake controller voltage finally gets high enough somehow reconnect? If I get out of the truck, unplug, and replug the trailer harness (with truck still running), the issue goes away as well.

Daniel Bare · August 24, 2023

Has anyone looked into installing a dc/dc charger to remedy this problem? Something like this.

https://www.amazon.com/Victron-Orion-TR-Isolated-Charger-Supply/dp/B0851TPKV7/ref=psdc_15719911_t2_B07ZKG396Y

It takes an input voltage from the truck, anywhere from 8-17 volts, and gives the appropriate output voltage 10-15 volts depending on your battery bank in the rv.

They are pretty common when installing solar and lithium batteries in RVs. They prevent the higher voltage of the RV battery system back feeding the truck through the 7 pin plug.

I have a 2024 LTZ on order to tow my Airstream travel trailer. I have solar and lithium batteries so hoping this would resolve the problem.

Mark Schroeder · August 25, 2023

I had the 2024 brake controller cutting in and out issue pulling my fifth wheel w/ 375w solar and lead acid battery. Put a Blue Sea Systems 6006 m-Series Battery Switch on the positive wire between the solar panel and the solar controller. Turned off the solar while traveling and got rid of the issue. Would really like to hear from those that put a diode between the truck and the trailer as to how that worked out (including specifics on which one you used if it worked well). If that works I'd like to put that diode inline, leave the solar on while traveling, and also be lithium ready.

Side note: 2024 with 1200 miles and the starting battery took a crap and had to get a warranty replacement thru the dealer.

Edited August 25, 2023 by Mark Schroeder

kf9yr · August 25, 2023

On 8/24/2023 at 9:38 AM, Daniel Bare said:

Has anyone looked into installing a dc/dc charger to remedy this problem? Something like this.

https://www.amazon.com/Victron-Orion-TR-Isolated-Charger-Supply/dp/B0851TPKV7/ref=psdc_15719911_t2_B07ZKG396Y

It takes an input voltage from the truck, anywhere from 8-17 volts, and gives the appropriate output voltage 10-15 volts depending on your battery bank in the rv.

They are pretty common when installing solar and lithium batteries in RVs. They prevent the higher voltage of the RV battery system back feeding the truck through the 7 pin plug.

I have a 2024 LTZ on order to tow my Airstream travel trailer. I have solar and lithium batteries so hoping this would resolve the problem.

I have a CTEK 250SE DC to DC charger in my Featherlite Enclosed Car hauler. I also have 400 watts of solar and a 200ah lifepo4 battery.

The DC input from the truck 7pin would be used to keep the battery charged if the solar panels aren't supplying enough current.

I haven't used the trailer for any long trips with my 2024 GMC but I didn't have any brake controller messages while setting up the invisible trailer camera / TPMS sensors.

mcausey · August 25, 2023

Grand Design RV has a fix out that adds a Battery disconnect between the Solar controller and the battery until GM fixes this crap.

Mike

Edited August 25, 2023 by mcausey

Rototerrier · August 25, 2023

Great news from GD. Thank you for sharing. Basically doing at the factor what all of us have resorted to doing on our own.

UWSkier · August 25, 2023

20 hours ago, Mark Schroeder said:

I had the 2024 brake controller cutting in and out issue pulling my fifth wheel w/ 375w solar and lead acid battery. Put a Blue Sea Systems 6006 m-Series Battery Switch on the positive wire between the solar panel and the solar controller. Turned off the solar while traveling and got rid of the issue. Would really like to hear from those that put a diode between the truck and the trailer as to how that worked out (including specifics on which one you used if it worked well). If that works I'd like to put that diode inline, leave the solar on while traveling, and also be lithium ready.

Side note: 2024 with 1200 miles and the starting battery took a crap and had to get a warranty replacement thru the dealer.

Haven't had a chance to install the diode and test yet but hope to soon. Just need time to wire it in when it's not a million degrees here in AZ. I'm planning to use this diode.

https://www.amazon.com/dp/B007HRO4X8?ref=ppx_yo2ov_dt_b_product_details&th=1

Going to use that instead of the switch on the solar, because I sometimes like to drive with my generator powering the trailer to run the air conditioner.