Which parts fail
Components named in complaints (battery, alternator, wiring, ignition, instrument cluster, infotainment).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 GMC Sierra 1500 owners, lightly cleaned up (personal details are redacted by NHTSA).
Less than 5 minutes after my husband and 2 children parked the car and came inside, a neighbor walking rang our doorbell to let us know there was something on fire in our driveway. We ran to the back to find his truck engulfed in flames coming from the engine. We quickly called 911 and exited the house/property. The truck continued to burn with 20-25 foot flames and very black smoke for about 40 minutes until the fire department was able to control the fire. The fire was hot enough that the entire engine was significantly burnt, the seats and steering wheel were gone, the glass shattered and melted, and the tires exploded and melted. Thankfully, everyone was out of harms way and safe through this incident. However, it has been extremely traumatic on my family and neighbors and has taken a lot of time and energy to try to deal with this. …
My truck had smoke rolling out at work when I noticed it. Tried to put it out it Burnt my hands ! destroyed the inside I had it towed and insurance investigator said it was do to a brake controller for the trailer. And I took it to get estimate and the service dept said it was do To brake controller my truck was totaled my wallet toast my coat was toast my I phone my deposit my truck i drove daily to work out of and personal. General Motors would not help I called the. First. Then I was frustrated called my insurance they started a claim and low balled me now I lost 2 months of work bills stacked and low ball price on what the offer was) and haven't gotten one yet. Called gm back they said I had an active claim they woundenr help it's there defect I lost my job my mind etc on this. Two investigators state the same thing even there service dept. A gm service dept said the same thing. …
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 50-65 MPH on an incline, the contact believed that the transmission was slipping or there was a misfire coming from the engine. The contact stated that the vehicle failed to restart automatically after the engine AUTO Start/Stop system was engaged after a complete stop. Additionally, the contact stated that after driving for a while, the vehicle went into LIMP Mode. The check engine warning light and other warning lights were illuminated. The vehicle was taken to the dealer to be diagnosed. The contact related the failure to GM Campaign Number: N252515590 (Corroded Ground Strap); however, the dealer had informed the contact that the vehicle was not covered because the VIN was not included and there was no warranty coverage on the vehicle. The vehicle was not yet diagnosed or repaired. …
The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at various speeds with the ONSTAR/GPS, turn-by-turn driving directions activated, there was an unknown notification flashing on the instrument panel and radio. The speedometer was obstructed and failed to work as needed. The screen sporadically went blank. While depressing the dismiss button on the steering wheel, the button failed to correct the failure. There were no warning lights illuminated. The vehicle was taken to the local dealer and the system was rebooted; however, the failure recurred. The vehicle was taken back to the local dealer and the contact was informed to turn off the vehicle, open the door, and then restart the vehicle to reboot the vehicle. …
The contact owns a 2021 GMC Sierra 1500. The contact stated while the vehicle was parked, the contact attempted to turn off the vehicle; however, the vehicle remained running. A message was displayed to shift to park(P). The contact stated that the lights, radio, and other functions remained operational. On another occasion, the vehicle jerked, and the steering was difficult to turn. The dealer was contacted; however, the vehicle had not been taken to be diagnosed or repaired. The contact also stated that the trunk failed to fully close. The message that the trunk was open was displayed. The contact attempted to close the trunk and message on the displayed was turned off; however, the trunk remained slightly open. The vehicle was not taken to be diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 63,315.
The contact owns a 2021 GMC Sierra 1500. The contact stated that when pulling a trailer with electric brakes with their vehicle, a warning light stating to check the trailer would illuminate on their instrument panel. The warning light would also state that the electric brakes had disconnected and then reconnected shortly after. The failure would occur on a consistent basis. The main control computer system in the center where the radio is located would flash the message that the trailer brake gain not been recalled. The contact contacted the dealer who confirmed that the computer system was known to have an issue due to the interference between the electric brakes and the LAD lights on the vehicle, however, there was no recall. The vehicle had not been repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 21,000.
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving 60 MPH, there was an abnormal knocking sound coming from the engine compartment, after which the vehicle lost motive power. The contact was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was taken to an independent mechanic, who determined that the engine had seized. The contact was also informed that the fuse box needed to be replaced. The vehicle was repaired, but the failure reoccurred. After investigating the failure, the contact related the failure to NHTSA Action Number: PE25001 (Engine, Engine and Engine Cooling). The manufacturer was not notified of the failure. The failure mileage was 63,000.
The contact owns a 2021 GMC Sierra 1500. The contact stated while driving at an undisclosed speed, the transmission slammed into gear and the rear wheels locked up. In addition, the vehicle decelerated independently. The vehicle was driven to the shoulder of the road and turned off. The vehicle was restarted, and the contact noticed that the vehicle was independently reset. The vehicle was taken to the dealer where it was diagnosed with a failed wiring harness. The contact was informed that the wiring harness needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and a case was filed. The contact was advised to contact the NHTSA Hotline and report the failure. The failure mileage was approximately 60,129.
The contact owns a 2021 GMC Sierra 1500. The contact stated that there was an abnormal change with the RPM. There were no warning lights illuminated. The contact received notification of NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); however, the part to do the recall repair was not yet available. The local dealer was contacted. The dealer received an email from the manufacturer, but the verbiage was incorrect to move forward with the repair. 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 39,000. VIN tool confirms parts not available.
The contact owns a 2021 GMC Sierra 1500. The contact stated that while driving approximately 25 MPH near the residence with the contact's daughter as a passenger, the vehicle experienced a complete loss of motive power when depressing the accelerator pedal. Several unspecified warning lights illuminated. The contact and the passenger pushed the vehicle to the residence. The vehicle was towed to an independent mechanic, where it was diagnosed that the electrical system experienced a severe power loss and the electrical modules were damaged. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 89,000.
Electrical complaints in other Sierra 1500 years
Frequently asked questions
How common are electrical problems on the 2021 GMC Sierra 1500?
NHTSA has 76 complaints about the electrical system of the 2021 GMC Sierra 1500, 13% of the model year's 594 complaints. The component named most often is integrated trailer brake control (2 mentions).
Is there a recall for 2021 GMC Sierra 1500 electrical problems?
No. NHTSA lists no electrical system recall for the 2021 GMC Sierra 1500, though it has 7 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2021 GMC Sierra 1500 electrical problems start?
Half of the complaints with a recorded mileage happened before about 39,000 miles, and 50% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 3 fires and 1 injury to electrical system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.