2021 GMC SIERRA 2500 Complaints

Headlights and turn signals failed. Flickering of various lights (Daytime running lamp, low beam, high beam, turn signals) followed by total failure. 3700 dollar repair at dealer to replace both headlamp assemblies. Barely over miles of warranty, but still in the 3 year warranty time period. Not having forward lighting is of course a major safety issue. Vehicle should be recalled. Many others are having the issue.

The contact owns a 2021 GMC Sierra 2500. The contact stated while driving 40-55 MPH, the vehicle started losing motive power. The contact stated while pulling into a nearby independent mechanic shop, the vehicle started jerking significantly and stalled midway. The check engine warning light was illuminated. The mechanic diagnosed the vehicle with transmission failure. The vehicle was towed to the residence. The local dealer and several unknown dealers were notified of the failure and informed the contact that the transmission assembly was not available and could not be ordered. The vehicle was towed to CJ's Transmission, where the transmission was taken apart. The mechanic determined that the transmission needed to be replaced. The vehicle was being repaired with a rebuilt transmission. The contact received notification of NHTSA Campaign Number: 24V797000 (Power Train); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the failure and offered a modest monetary compensation for the repair. The failure mileage was approximately 134,000. Parts distribution disconnect.

Seems to be a known problem according to a google search but brake fluid leaking from brake pedal onto drivers floor mat. Seems to be a bad brake booster according to google and happening for some at a few weeks to a couple months old in the newer ones. I noticed first on my truck around 58,000 miles.

On 11/21/24 noticed passenger headlight day light running light flickering. On 11/22/24 right turn indicator intermittent fast blink, dash message stated turn indicator failure. Once home, inspected passenger headlight assembly. Found DRL, turn signal, and low and high beam head lights were inoperative. On 11/25/24 went to GMC dealer/service. Staff seemed aware of issues and stated they are common, that they carry the $1,400 sealed assebly in stock. Vehicle is 4 months over warranty, but only has 29,000 miles. There is no visible damage to the assembly, but there is visible condensation inside the lens. GM has a published service bulletin, 01-08-42-001P, that specifically addresses this issue for my vehicle. The earliest date the issue could be diagnosed/service date is 12/10/24. A complete failure of this non-servicable headlight assembly is an absolute safety issue. Decreased daytime visability with the loss of one of two Daytime Running Lights, the lose of the front turn indicator to alert other drivers of my intentions, the lose of a set of low and high beam headlights. As mentioned, there assembies are a sealed LED light assembly. If any one of these lights fail, the only remedy is the replacement of the entire unit with a $1,400 part. GM has had multiple recalls of this same issue among their vehicle, but continues to produce the same failing pieces.

The contact owns a 2021 GMC Sierra 2500. The contact stated that no visible tailgate was attached, and the contact was unaware if the vehicle had been repaired under NHTSA Campaign Number: 24V060000 (Latches/Locks/Linkages); however, the recall had been marked as completed under the VIN. The vehicle was taken to a local dealer where they advised the contact that the recall repair was completed. The vehicle was taken to another local dealer, Littleton Chevy (851 Meadow St Littleton, NH 03561); for a second opinion and was informed that the recall repairs had not been performed. In addition, the contact stated that the tailgate was replaced with an after-market part due to backorder issues. The contact stated that there was no failure experienced with the original part. The manufacturer was made aware of the issue. The contact had not experienced a failure. The failure mileage was 125,000.

I purchased a 2021 GMC Denali 2500 in December 2023. A couple days after purchasing the vehicle I received a message on the dash saying the front camera was not working. I took the vehicle into the dealership where they said they reset the computer and nothing was wrong with the vehicle. One month later I was involved in a collision where a vehicle turned in front of my vehicle and the Automatic Emergency Braking failed to activate. I applied the brakes but due to my delayed reaction time 1.5 seconds, I broadsided the small vehicle with my large truck. Luckily the speed was only 20 mph and no one was hurt or killed. At this time I did not know my vehicle was equipped with AEB. In October I discovered through GM and a different dealership that my vehicle was equipped with Automatic Emergency Braking. I have had several occasions when the AEB including the crash where the AEB should have activated but never did. In 11 months I have never had the AEB activate. I took the vehicle into the dealership where I bought the vehicle and they said their computer said everything was operating correctly. The tech never drove the vehicle where the AEB should have activated. I have driven many cars and even the same model vehicle as mine, so I know what the AEB feels like and my vehicle the AEB is not working. The dealership told me to take the vehicle they checked everything GM told them to check. When I talked to GM they told me to immediately take the truck to the dealership and the dealership did nothing.

The contact owns a 2021 GMC Sierra 2500. The contact stated while driving approximately 70 MPH, the vehicle lost motive power. The contact stated that the message “Vehicle will not Exceed 50 MPH" was displayed. The vehicle was taken to a dealer and remained for over four months after being diagnosed that the solenoid valve and transmission needed to be replaced. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 50,000.

The contact owns a 2021 GMC Sierra 2500. The contact stated while driving approximately 25–35 MPH, the tailgate unlatched and opened unexpectedly. The contact stated that while the vehicle was parked, the tailgate opened independently. The contact stated that the tailgate down message was displayed after the failure. The vehicle was taken to an independent mechanic at a body shop, who determined that the failure was due to the touchpad. The vehicle was repaired. The vehicle was taken to a body shop, where it was replaced. The contact received notification of NHTSA Campaign Number: 24V060000 (Latches/Locks/Linkages); however, the part to do the recall repair was not yet available. The local dealer was not contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The failure mileage was approximately 49,000. Parts distribution disconnect.

3 year old truck. The left headlight enclosure gained water and caused the whole headlight system to have issues. Water caused the Headlights to Flash high beams (both), turn off and blinkers not to work. This defect the whole side that is effective. This can cause other drivers or the owner to have an accident. 6 months later, Now the right side headlight is doing the same. I’m out of warranty with only 40k miles. The seal is not strong enough to keep water out the enclosure. This can also cause the whole light system to shut down while driving. Very dangerous especially at night.

My tailgate unexpectedly open as I was driving down the road. (2021 GMC 2500 Denali Sierra) This was the second time this has happened and lost things driving down the road. (3 propane tanks and a small grill the first and then an air compressor the second time) Both times it happened I opened and closed the tailgate with the vehicle running. Both times I was unaware of tailgate opening and did not notice until I got home. The first time it happened I thought it was operator error but after this weekend, I looked into this and see there was a recall on it this month. I still felt it was necessary to report incidents.