The 2024 GMC Sierra HD is included in a new customer satisfaction program issued by General Motors, which includes a fix for a problem that can cause intermittent loss of trailer brake function in certain units of the pickup.
The involved vehicles include 2024 GMC Sierra HD trucks that include the integrated trailer brake controller (RPO code JL1) feature, Customer Satisfaction Program number N232414840 says, with the brake issues caused by a potential fault in which voltage feedback occurs.
In affected GMC Sierra HD units, the trailer brakes stop functioning when the vehicle responds to a false short to ground detected by the Trailer Brake Control Module, causing it to shut off the trailer brakes. The false short is also displayed on the pickup’s dash. It occurs when the voltage of the vehicle battery is exceeded by the voltage of the trailer battery, resulting in feedback in the system.
Dealers are instructed by GM to apply the now-available fix to 2024 GMC Sierra HD units brought in for the issue, present at the dealership for other service, or still present in their inventory. To end the problem and cause the trailer brakes to function normally and properly at all times, service personnel should install a new Trailer Brake Control Module. These modules are in limited supply and should not be ordered as shelf stock.
The remedy offered by the customer satisfaction program is available free of charge to all affected 2024 GMC Sierra HD owners through August 31st, 2026. The dealership should send notification letters to recent purchasers informing them of both the issue and the available free fix.
It is currently unclear exactly how many GMC Sierra HD units are affected by the problem, although GM informed us that the majority of those are currently in dealer possession or on their way to dealerships. As a reminder, the trailer brake controller (JL1) is optional on the Pro trim level and equipped as standard on the SLE, SLT, AT4, Denali and Denali Ultimate trims. The integrated trailer brake controller is also required to order in conjunction with the optional 6.6L V8 L5P turbodiesel Duramax engine on the Pro.
Under the hood, the 2024 Sierra HD cradles the naturally aspirated 6.6L V8 L8T gasoline engine as standard, offering output of 401 horsepower at 5,200 rpm and 464 pound-feet of torque at 4,000 rpm. The aforementioned 6.6L L5P turbodiesel Duramax engine is uprated for 2024, and now develops 470 horsepower at 2,800 rpm and 975 pound-feet of torque at 1,600 rpm..
A more-capable variant of the GM T1 platform underpins the 2024 Sierra HD. Production is takes place at the GM Flint plant in Michigan.
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Comments
Ok so someone seen my post earlier on Chevrolet HD trucks and I asked about GMC HD trucks. So now I can take my truck in for updates.
NOW how about a good release of the Ultimate Denali up fitters switch package! It supposly delayed to ’25! Really GM we need that package. Let’s release the real deal.
About time – trying to pull my trailer and having this issue for several months now. Over 16,000 lbs. of trailer and loosing breaks – took you guys long enough. This should be a safety recall, putting families lives in danger. Way to go…..
AGREED! We too have been troubled with this since our 5th wheel purchase in June. We had to read about it on a YouTube video trying to troubleshoot the break problem on our own. When we took it into our dealership, the service department knew nothing about it. We had the new module installed and we are STILL HAVING ISSUES. This is totally a safety recall issue and we are lucky we haven’t had any accidents thus far. We have also had to cancel camping trips because of the unresolved problem. We spent money on new breaks and camper wiring fixes with no resolution. We are taking the truck back to the dealership and insisting on ANOTHER new module. GMC should contact all customers with this issue and never even sell the vehicle without the proper fix in place. Extremely disappointed in GMC.
GMC Sierra 2500 Denali Trailer Brake Issues—Dangerous and Unresolved After Multiple Attempts
We bought our 2024 GMC Sierra 2500 Denali in April 2023 with high hopes of towing our brand new Airstream Classic for full-time travel and remote work. Unfortunately, our experience has been nothing short of frustrating and even dangerous.
From the very beginning, we had problems with intermittent alerts like “check trailer wiring” and “service trailer brake system” while towing our Airstream. The dealership repeatedly told us the issue was with the trailer itself, so we went as far as driving to Airstream HQ in Ohio to have everything checked. After that, the issue persisted. Feeling like we were left with no other choice, we sold the Airstream at a massive loss of $70,000, thinking the problem was specific to that trailer, and then bought a Fifth Wheel.
To our disbelief, we encountered the exact same issue with the new trailer—intermittent loss of trailer brakes. This wasn’t just an annoyance; it was unsafe. And then, on top of that, the truck’s tailgate opened while driving, leading to the loss of our luggage on the freeway—this happened multiple times over the past year.
We’ve been back to multiple GMC dealerships, taken the truck in for service countless times, and even had the trailer brake control module replaced after being informed of a recall. Yet, the problem remains unresolved. Most recently, after another supposed “fix” involving a fuse replacement, the brake failure happened again—this time on a downhill road, which was terrifying.
This entire ordeal has not only cost us significant money, but it has put us in dangerous situations. We live in our trailer full-time, and we’re now stuck in a place we don’t want to be, with a truck that is unsafe to tow.
The dealership keeps pointing fingers at the trailers, but after two different trailers and multiple service visits, it’s clear the problem lies with the truck itself. We’re at the point where we’re considering legal action because enough is enough.
Has anyone else experienced similar issues with GMC trucks? We are considering speaking to an attorney at this point for legal assistance. We’ve been patient, but this has become unacceptable. We want our money back.
We have had the exact same issues with our 2024 GMC 2500 HD. We also have had multiple visits to the dealerships and they all deny that it’s a problem with the truck. We’ve spent over $1000 on our camper trying to resolve the problem, but it always points back to the truck. Surprisingly, at two separate dealerships, they were amazed that this is a problem and that they never heard of it before. I find that very hard to believe because service bulletins have been issued for this problem. Thus far, GM has followed the suggestions of the service bulletins issued. Break module has been replaced as well as one of two electrical suggestions they have made. Neither of which has resolved the issue. Maybe if the hundreds of customers banned together and threatened legal recourse GM will do what is right and make this a safety issue recall and fix it!! Maybe it will take a class action lawsuit for GM to resolve this problem once and for all. How can they keep selling these vehicles with the knowledge that this problem exists.
I completely agree with you. We’ve been facing the same trailer brake issues with our 2024 GMC 2500 HD and have also been through countless dealership visits with no real solution. Like you, we’ve been told the problem lies with our trailer—despite already selling our Airstream at a significant loss and buying a new Fifth Wheel, only to have the same issues. It’s beyond frustrating and, most importantly, dangerous.
We’ve had the brake module replaced and followed all service recommendations, but nothing has worked. Honestly, a class action lawsuit may be the only way to get GM to take responsibility and treat this as the serious safety issue that it is. It’s clear this isn’t an isolated problem, and it’s shocking that GM continues to sell these vehicles knowing the issue exists.
If enough of us band together and pursue legal action, maybe GM will finally be forced to do the right thing. Thank you for sharing your experience—it helps to know we’re not alone in this, and we’re fully on board with taking legal steps if that’s what it takes.
If anyone does not believe our stories, go ahead and Google 2024 GMC or Chevy 2500 HD brake control module issues. There are countless stories all saying the same thing.
We didn’t have the trailer brake problem, now after the recall we have the problem.
We have had the same issues with our 2024 3500 Denali HD . Spoke to two dealerships while on the road – they both were aware of the issue, but didn’t seem to have a solution, and of course couldn’t get us in for at least 3 days. The dealer we purchased from didn’t have a clue. We got the same answer – it’s the RV. RV dealership suggested an adaptor that they said has worked for others. Will let you all know if it works!