2020 GMC SIERRA 1500 Complaints
View complaints related to 2020 GMC SIERRA 1500. The complaints found here are submitted by actual consumers with first hand experience. There are more than 440 complaints submitted for the 2020 GMC SIERRA 1500. You can submit your own complaint to the NHTSA or call the Hotline, Monday-Friday 8am to 8pm at (888) 327-4236, TTY: (800) 424-9153.
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2020 GMC SIERRA 1500- Duluth, MN
Rear Sliding Glass window frame has cracked and allows water to enter the cab of the vehicle. Yes this is available for inspection. The water entering the cab of the vehicle can create mold from moisture build up if left untreated. I was able to have the dealer service center confirm the issue noted in [XXX] but they were unable to repair it as it is outside of warranty. I was able to have an independent 3rd party glass company confirm that it was indeed a manufacturers defect with a cracked housing and not an issue with sealant around the glass itself. No warning lamps or other indications other than water in the back seat of the vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Jerome, ID
Rear Window Leaks due to failed sealing at the factory. If not fixed will ruin interior components and possibly rust. Yes No No
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Phoenix, AZ
1. Valve Lifter Failure 2. While entering the [XXX] freeway and trying to merge into traffic the engine lost power and I had to swerve and brake to avoid an adjacent vehicle, and freeway traffic had to avoid my slowing down to pull over. 3.Yes, Van GMC in Scottsdale, confirmed lifter failure. 4. Yes, GMC Dealership 5. Absolutely no warning given INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Quincy, MA
The contact owns a 2020 GMC Sierra 1500. The contact stated while detailing the rear interior of the vehicle, the contact discovered water surrounding the rear windshield casing and the water was leaking into the rear seating. Additionally, the rear carpet was soiled with water. The contact used towels while attempting to soak up the water. The vehicle was taken to the dealer where it was diagnosed that the failure was due to the failed rear windshield glass fasteners. The contact was informed that the failure had damaged the rear carpet, padding, and the rear seat. In addition, the contact was informed that the carpet and padding needed to be replaced due to mold build up. The contact was informed that the vehicle was out of warranty coverage. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 31,000.
Source: HOTLINE VEHICLE OWNERS QUESTIONNAIRE -
2020 GMC SIERRA 1500- Sebring, FL
Lost break, second time this month, showing break failed 40 mph max speed, abs light on, break light on, and 2 more light on the car with antislipiring or something like that, the another one no idea what it is
Source: NHTSA WEB SITE -
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2020 GMC SIERRA 1500- Toms River, NJ
The back window leaks, I brought it in they told me it wasn't warranty so I paid to have it fixed. Still leaks.
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Peoria, AZ
Lifters Failed in November 2023 and had repaired major engine damage including 4 cylinders, cam shaft, lifters, gaskets etc. After major repair work done. Truck is now doing same exact thing in January 2024. The dealership is stating they will not look at the vehicle unless i buy a new battery. I asked them to try a used battery to see if that makes a difference. And then if it is the battery i will replace. I was hung up on after the technician doug Pedersen stated ill have a supervisor call you back.
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Vine Grove, KY
While driving, the power steering (electronic) failed. Driver Info Center gave no waring until the system failed. After failure the DEC gave a warning to "Service Poser steering".
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Outing , MN
Driving on state highway at posted speed. A deer ran into the right front and side of vehicle. Side airbags deployed. When the right side airbag deployed, it burned a hole in my passengers winter coat that completely went through the right sleeve forearm and scorched the sweatshirt that she was wearing under the coat. Smoke was visibly apparent in the cab of the vehicle. We thought the truck was on fire , then finally determined it was the sleeve of here coat.
Source: NHTSA WEB SITE -
2020 GMC SIERRA 1500- Cochranvile, PA
The rear window was leaking a substantial amount of water soaking the back seat. Had the service bulletin done, which did not work. Then under further inspection found cracks in the rear power window track. Dealer told me GM would not cover replacement because it was out of the 3 year warranty. Then was told it would cost me 1200 dollars to replace. GM should cover this because it will lead to black mold.
Source: NHTSA WEB SITE