024 GMC Sierra 2500 Denali Ultimate, which has suffered: -??Five catastrophic engine failures at highway speeds. -??Total brake failure, leaving the truck unable to stop. -??Severe electrical malfunctions, including flickering headlights at night. -??Retaliatory actions from General Motors after I refused to waive my legal rights. I have documented proof, including GM-??s own service records, emails, and a 7-minute recorded statement from GM-??s highest-level technician, confirming that GM installed the wrong computer module (1500 series instead of the required 2500 series) in my truck. Additionally, I have evidence that GM executives instructed technicians to conduct diagnostics, take apart the engine, and reassemble it-?"but NOT repair the defect-?"after I refused to sign an affidavit waiving my rights. Due to these failures, I suffered a dislocated shoulder in one of the incidents, and my [XXX] daughter remains traumatized to this day. Given the immediate danger this defect poses to other GMC Sierra 2500 owners, I respectfully request that NHTSA open an investigation and consider issuing a recall before a tragedy occurs. 1. Engine Failures Since 3,000 Miles -?" GM-??s Own Work Orders Confirm Issue Since purchasing my 2024 GMC Sierra 2500 Denali Ultimate, I have experienced five catastrophic engine failures, all occurring while traveling at highway speeds (70 mph): -??The truck suddenly lost power, dropping from 70 mph to 5-10 mph within seconds. -??This created an immediate risk of being rear-ended or losing control on the highway. -??GM-??s own service records confirm that my engine issues began at just 3,000 miles. -??GM dealerships misdiagnosed the issue FOUR TIMES, returning my truck to me in an unsafe condition. -??The real cause was only identified after the FIFTH failure, when a GM-certified head technician finally determined that GM had installed the wrong computer module (1500 series instead of 2500 series). This means that for months, GM knew my vehicle w INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA

- Richmond, TX, USA

Trailer brake controller will intermittently stop working. -??Check trailer wiring-?? will show up randomly on the display and no trailer braking will be available. This has happened with 3 different trailers. The trailer wiring was gone over and the issue is with the truck. Trailer brakes work with other trucks and aftermarket trailer brake controllers. GMC and dealer were notified and no fix is available. Researching online there are several complaints about this. The trailer brake signal should default to being sent similar to all aftermarket trailer brake controllers. This would be much safer rather than not sending the brake signal at all. This HD truck is rated to tow trailers over 20,000lbs and without trailer brakes it causes an extremely dangerous situation. I was forced to pull over on the highway and purchase an aftermarket trailer brake controller to continue safe travel.

- Fort Walton Beach, FL, USA

Transmission and transfer case leaking. Masters cylinder ( brake booster) leaking

- Hackettstown , NJ, USA

I purchased a 2024 GMC 2500 HD truck to pull a 2021 8,000 lb gvw camping trailer that is equipped with electric trailer brakes. My trailer has functioned perfectly related to the trailer brakes with my previous vehicle (2011 Toyota Tundra). With the GMC 2500, at approximately 3000 miles on the vehicle, a -??trailer brake disconnected or disabled-?? and -??check trailer wiring-?? warning began popping up on my information center of the truck. The trailer braking system would not function, though all other functions of the lighting and camera systems to the trailer worked indicating that the wiring and grounding were not an issue with the trailer. The brake system would intermittently return to normal. And then this warning and disconnected condition (i.e. no functioning trailer brakes) would return. This occurred rapidly, and very frequently. GMC has acknowledged a problem with some vehicles with this problem by publishing a TSB that purports to correct this issue (23-NA-149) that recommends replacement of the trailer brake control module (part no. 212327200000019B). I had this repair performed while on a trip in South Dakota away from my home state in Arkansas and the truck and trailer functioned as normal for approximately 3000 miles of towing. However, the issue has returned and my local GMC dealer repair shop (Little Rock, AR) places the blame on the trailer and not the truck. Towing with this 2024 GMC 2500 HD is very unsafe to the occupants and any others on the road due to loss of braking while towing a heavy load or navigating steep grades with a trailer equipped as described. This problem is now all over GMC/Chevy truck forums and is not just me or my combination. This issue is gonna get people killed.

- Little Rock, AR, USA

The contact owns a 2024 GMC Sierra 2500. The contact stated while driving at an undisclosed speed, the sun struck the solar panel used to charge the battery, and the surge from the battery entered the pigtail going through the truck, and disconnected the brake module, causing it to become disengaged from the vehicle. The contact took the vehicle to the camper and vehicle dealer who both stated there was no issue for concern. The vehicle was not repaired. The manufacturer of the camper and the vehicle were made aware of the issue. The vehicle failure mileage was 8,000.

- Clarksville, TN, USA

The contact owns a 2024 GMC Sierra 2500. The contact stated while stopped at an intersection, the vehicle moved forward while the brake pedal was fully depressed. The contact also stated on a level surface, the vehicle accelerated about 4 MPH without the accelerator pedal being depressed. The failure occurred on several occasions. The vehicle was taken to the dealer where the failure was duplicated; however, the dealer stated that the vehicle operated as designed. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 100.

- Dayton, OH, USA

Towing an RV with solar panels. When the trailer battery becomes fully charged and has a higher charge than the vehicle battery, the trailer brake control module becomes disabled. When this occurs, you have no trailer brakes. Combined weight of truck and RV exceeds 20,000 pounds. Trying to stop with only truck brakes is dangerous, especially if you are on a decent. I not only believe this to be a safety issues, but somebody is going to get killed.

- Macomb Township, MI, USA

While towing our RV trailer the trailer brakes become disabled. This is a known problem to GM and they have a TSB (23-NA-113) "Information on Trailer Brake Disabled or DTC Stored" This is a know problem and GM solution seems to cast the blame on the trailer manufacture.

- Lawrenceburg, IN, USA

When attached to a trailer with solar panels, the truck will intermittently disconnect the trailer electronics which disables the trailer brakes and trailer lights. This is because the solar energy is back flowing to the truck via 7 pin connector and overloading the circuit. Having a truck disable the trailer brakes and lights intermittently is very dangerous. Earlier model years of this truck do not suffer this issue. GM is aware and has TSB but no solution has been found on the truck side without disabling the solar panels on the trailer.

- Town And Country, MO, USA