2025 GMC Sierra 2500

My 2025 GMC Sierra 2500 experienced repeated electrical failures that caused complete battery drainage and multiple overnight no‑start conditions within the first year of ownership. These failures occurred in extreme desert heat, where temperatures in [XXX] reach 120°F. A vehicle that repeatedly fails to start in these conditions creates a serious safety hazard, including risk of heat‑related medical emergencies if stranded. The defect persisted despite multiple repair attempts and two battery replacements. The dealership ultimately told me I would “need to replace batteries as needed,” instead of diagnosing the underlying electrical issue. Detailed Description of the Problem Multiple overnight no‑start incidents Several jump‑start events required XXX – 15,265 miles: Battery replaced due to electrical drainage XXX: Battery replaced again for the same defect Electrical system continued to fail after repairs Dealer advised ongoing battery replacement rather than addressing root cause The truck was unreliable and unsafe in extreme heat. A no‑start condition in 120°F temperatures can leave occupants stranded without air conditioning, posing a life‑threatening risk. Frequency of the Problem The electrical failure occurred multiple times over several months, including late 2025, early 2026, and again in mid‑2026. The defect was consistent and repeatable. Consequences Risk of being stranded in extreme heat Loss of air conditioning during no‑start events Potential for heat exhaustion or heat stroke Vehicle unreliable for daily use Safety hazard for driver and passengers INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My 2025 Sierra 2500HD repeatedly displays “Trailer Brakes Disabled—Service Required” with a lithium- and solar-equipped trailer. The truck passes the EL-52641 simulator, but the failure occurs intermittently while towing and resets after Park or reconnecting the trailer. This closely matches the higher-trailer-battery-voltage/backfeed condition described in N232414840. Please open a TAC case and determine whether my 2025 has the revised Trailer Brake Power Module or whether GM engineering authorizes module replacement.

Power steering pump failed when decelerating after 9500 miles. When power steering pump fails, power assisted braking also fails. Upon deceleration, I could not turn the steering wheel at all or stop the vehicle without extreme pressure on the brake pedal. I narrowly avoided impact with a concrete barricade at the entrance to a parking lot. GM issued a technical bulletin (DCS7112) on January 16, 2025 identifying the problem and failure and directing dealerships to replace the pump on inventory vehicles. No mention was made to repair or notify owners of the potential problem.

The contact owns a 2025 GMC Sierra 2500. The contact stated that the front driver’s side door handle failed to operate as needed, and the contact was unable to exit the vehicle through the driver’s side door. The vehicle was taken back to the dealer, and a new handle was ordered. The part was replaced under warranty. Soon after the repair, the liftgate failed to open or close as needed and became inoperable. The vehicle was taken back to the dealer for the liftgate to be serviced under warranty. The manufacturer was not notified of the failure. The vehicle remained with the dealer unrepaired. The failure mileage was approximately 300.

On highway taking an exit. The brake pedal sank and did not engage at normal pressure, I had to push the brake all the way down for it to engage. Concurrently the steering wheel locked up where I could not turn the wheel at all. I drove straight through the exit ramp to the entrance ramp, luckily no one was entering the highway at the same time. I very well could have hurt some one else or myself. The steering wheel finally engaged where I had full power steering again and I was able to remove my truck off the highway and cautiously drove to a parking lot to get it towed. I have not tried to drive sense incident as it is at the dealer for service. The GMC Dealer has not inspected the vehicle yet, they are backed up with other services. There were no warning lamps at the time nor before the incident. Symptons see bellow. I have had issues with the brakes and it has been to the dealer 4 times including this incident, Service issue #1 at 21,501 miles -Breaks were pulsating, squealing and rough and it was shaking the steering column - The smell of burning breaks was present after drives -Solution they sanded down the hot spots on both rotors and pads for the front brakes Temporarily fixed the breaking and steering column shaking ( it did not solve the burning break smell problem. Service issue #2 at 28,142 miles Breaks were pulsating, squeaking, and steering column shaking - The smell of burning breaks was still present after drives. solution new front brake pads and rotors. Service issue #3 at 39,893 miles Rear brakes locked up while taking a turn on to a street Breaks were pulsating Squeaking and steering column shaking Smell of burning breaks is still present after drives solution machine front brake rotors. could not reproduce brake locking issue Final issue as mentioned above #4 @43,426 miles I cant help but think the constant break issues were warning signs.

Component / System Failure The exhaust system, specifically the exhaust manifolds and previously the EGR system components, appear to have failed or malfunctioned, allowing exhaust gases to enter the passenger cabin. The dealer initially replaced the EGR cooler diverter on December 23, 2025. However, the condition persisted. On February 3, 2026, cracked exhaust manifolds were identified by the dealership, and a major front-end teardown was advised to complete the repair. The vehicle is currently available for inspection upon request. ⸻ How Safety Was Put at Risk The malfunction allowed exhaust gases, including carbon monoxide, to enter the passenger cabin during vehicle operation. Carbon monoxide readings inside the cabin reached up to 50 parts per million (ppm) while driving. Carbon monoxide is a toxic gas that can cause: •Headaches •Dizziness •Impaired concentration •Nausea •Vision disturbances Because carbon monoxide is odorless and colorless, this presents a significant safety risk, particularly at highway speeds where driver alertness is critical. The exposure occurred while operating the vehicle in normal driving conditions. This created a potential risk of driver impairment and increased risk of collision. ⸻ Has the Problem Been Reproduced or Confirmed? Yes. The vehicle was presented to the dealership three times for the same exhaust intrusion concern: •December 16, 2025 •December 29, 2025 •February 3, 2026 During the February 3 visit, the dealership confirmed cracked exhaust manifolds requiring major disassembly for repair. The carbon monoxide readings were observed during vehicle operation. The exhaust odor and intrusion symptoms were consistently present following the first attempted repair. ⸻ Has the Vehicle Been Inspected by Manufacturer or Others? The vehicle has been inspected by the authorized dealership on multiple occasions. Two manufacturer customer care cases were opened.