2020 GMC Sierra 1500 window and wiper problems

VISIBILITY/WIPER

The frame of the back window is cracking allowing water to come in through the back glass. This is causing the headliner and other components such as air bags and other electrical components to get wet and damaged. This could cause risk of fire or failure of safety components within the vehicle such as air bags, cameras and other sensors. With water intrusion comes the high risk for mold to develop and cause serious health risks. GMC is aware of this issue and will not agree to repair it. A GMC dealer has inspected the glass and said it was a faulty seal but since it's not in the 3 year warranty window, it's not covered. Independent auto glass companies state they have seen this issue many times and the glass seal is faulty. GMC should do the right thing and fix this issue. This devalues the vehicle and the GMC brand and poses serious risks to driver. I have created a case with GMC and submitted photos, videos and dealership estimates for proof.

NHTSA complaint #11726576 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

Back window leaks down onto electrical compents and causes mold behind rear seat, plus staining mold on headliner

NHTSA complaint #11712976 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

The morning of December 12th, 2025 I used my vehicle to transport my daughter approximately 5 miles round trip from our home to drop her off at daycare and then I returned home. I used my front and rear defrost elements to expedite removal of heavy condensation which had formed on all windows overnight. This was approximately 7 AM. I parked my truck in the driveway and went inside until approximately 11:45 AM when I went to leave in my truck and noticed the rear sliding window had shattered. The window shattered and distributed tempered glass fragments all over the inside of the cab. Only approximately 10% of the window remained intact. I then reviewed the security camera footage from my driveway and discovered that the window failed entirely on its own with nothing hitting/striking/touching the window, nor any humans or animals in the vicinity. I attempted to take the vehicle to a GMC service department this morning (Dec 13) but due to their demand to keep the vehicle for 2-3 days to investigate yet unable to provide a loaner vehicle, I was unable to leave the vehicle in their possession and returned home. I plan to continue to contact GMC dealership service departments in hope I can find one which can provide a loaner vehicle, as I will need transportation to and from work in the coming days. I do have video footage of the incident although I am unable to add it below.

NHTSA complaint #11704848 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

The rear back glass is leaking water excessively in to the inside of the vehicle when it rains or gets washed. The vehicle is available at any time for inspection. The amount of condensation that accumulates on all the interior windows makes it impossible to see out of the vehicle. The defrost can not handle the amount of moisture build up. The Dealer knows about this condition and it has been verified by a window company. The manufacture knows and understands there is a problem and has put out a Technical Service Bulletin ( TSB 18‑NA‑383 ) for this issue but will not cover the repairs. GM knows that every single vehicle with this window designs from 2019-20121 will leak just outside the 3 year 36k mile warranty coverage. The cost of repair is approximately $2k. Dealer will not cover repair.

NHTSA complaint #11667795 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

Back window frame crack led to water intrusion which flooded electric module controlling speedometer and adaptive settings. Extremely unsafe driving with faulty electrical components unknown to me. Insurance and Dealership told me this is a common GMC occurrence. Cost is near $10,000 to make truck drivable.

NHTSA complaint #11575575 — an unverified report by a vehicle owner.

VISIBILITY:GLASS, SIDE/REAR:CRITICAL FASTENERS

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.

NHTSA complaint #11571977 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

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.

NHTSA complaint #11560834 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

The rear window on this vehicle is leaking water and has been for some time. It has become quite bad and is causing an odor and discoloration in the carpet. I could not find the cause of the problem until recently with the plastic cracking more. The vehicle has 41,000 miles and the dealer stated that is out of warranty and all repairs would be a cost to me. I researched this and have found it is a common fault this this vehicle.

NHTSA complaint #11546253 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

My back window leaks and gm has said that the warranty is over by years not miles it is not covered

NHTSA complaint #11515020 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

My rear window leaks there is a bulletin on it Call GM says it is not responsible for the repair because it is over on the years but not the mileage it’s clear they know about the problem it’s in many pickups that gm manufacture here is the bulletin file:///var/mobile/Library/SMS/Attachments/97/07/3010617D-BBB0-4FB8-859B-4BA5E2BE3F3A/Ed%20blakeslees%20truck.png

NHTSA complaint #11515021 — an unverified report by a vehicle owner.

VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM:REAR WINDOW

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving in the snow, the tire pressure and power steering warning lights illuminated. The vehicle was not diagnosed or repaired. The vehicle was taken to a dealer where it was confirmed that there were no recall or warranties that would cover the repairs for the warning lights. The failure mileage was 140,000.

NHTSA complaint #11455697 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

WHILE DRIVING ON A STATE HIGHWAY, I HEARD A "POP" SOUND, I SAW NOTHING CONTACT THE VEHICLE, BUT I THEN NOTICED THE WINDSHIELD WAS CRACKED. THE WINDSHIELD CRACKED FOR NO APPARENT REASON..

NHTSA complaint #11396371 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

WIPERS FROZE TO WINDSHIELD WHILE DRIVING WITH DEFROSTER ON MAX. DESIGN OF THE WINDSHIELD AND DASH MEANS WIPERS SIT LOWER THAN WHERE THE DASH AND WINDSHIELD MEET, AND NO WARM AIR FROM THE DEFROSTER CAN GET TO THE WINDSHIELD WHERE THE WIPERS SIT. THERE IS NO IN WINDOW DEFROSTER (LIKE REAR WINDOW) WHICH CAN HELP. MAJOR SAFETY ISSUE IN SNOW/ICE CONDITIONS.

NHTSA complaint #11390959 — an unverified report by a vehicle owner.

VISIBILITY/WIPER

BACK UP CAMERA IS AWFUL AT NIGHT. THIS IS A SAFETY ISSUE BECAUSE YOU CANNOT SEE ANYTHING WHEN BACKING UP. MY TRUCK HAS 323 MILES ON IT AND I WENT TO DEALERSHIP THEY SAID I WOULD HAVE TO LIVE WITH IT. THAT IS NOT ACCEPTABLE TO HAVE A SAFETY FEATURE THAT IS FAULTY.

NHTSA complaint #11362024 — an unverified report by a vehicle owner.