2022 GMC Hummer Ev Pickup

Visibility / Defogging / Defrosting issues are main safety concerns. Every winter for the last 3 years, the heater fails and blows only cold air. This is intermittent throughout the year, but recurring. With cold-weather driving conditions, it creates an unsafe driving experience when windshield and windows can't defog or defrost properly. The problem has been reported several times to the dealership and it was never fully resolved while under warranty. Each time I took the vehicle to the dealership for servicing with temporary adjustments. Dealership now states a heater module needs to be replaced at my expense although the same codes and part affected while under warranty. The component/part number needing replaced is part 85757074 (hybrid electric coolant heater module per dealership). There were several service vehicle warning lights and diagnostic codes were shared with dealership when dropped off for repairs.

Severe recurring roof water intrusion on 2022 GMC HUMMER EV; repeated failed repairs; interior rust/corrosion; safety concerns in high‑voltage EV. Vehicle: 2022 GMC HUMMER EV Edition 1
VIN: [XXX] Current mileage: ~12,000 miles
 
My vehicle has a recurring defect involving severe water intrusion into the cabin through/around the removable roof panels/roof sealing areas during rain. Despite repeated dealership repair attempts, the vehicle continues to leak. The ongoing water intrusion has caused visible corrosion (rust) on interior metal structures, including the floor area and seat rails/seat mounting areas. The corrosion indicates prolonged moisture exposure inside the cabin. The dealership has attempted to repair this water intrusion issue approximately six (6) separate times, and the defect remains unresolved. First documented repair attempt: 03/14/2023 (issue presented to dealership for correction) Most recent repair attempt/out-of-service: 12/29/2025 to 01/06/2026
The vehicle has spent weeks at the dealership across these attempts, including time waiting for parts and work completion. Even after these repairs, the vehicle is still leaking and the corrosion is still present. 
Because this is a high‑voltage electric vehicle, I am concerned that water ingress and corrosion are compromising electrical wiring/connectors and safety systems located in/near the cabin floor and seat areas (including areas where sensors and connectors may be present). I am concerned this could increase the risk of electrical short, malfunction of safety systems (including airbag sensors), and in a worst case scenario a fire risk if moisture reaches sensitive electrical components. I can provide photos/videos of active water intrusion and corrosion and all repair orders upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Same situation occurred twice. I was in the car at a red light. Car had been stopped for about a minute. Was on a slight decline, engine brake was engaged to hold car in position. Car was stationary completely. Suddenly tons of warning lights flash on the dash board 'One pedal driving unavailable', 'Service ESC', 'Service trailer brake system', 'Service active steering system', '4wd unavailable', service driver assist system , 'Speed limited to 36 mph'. First time this happened was June 2023. Dealer was unable to find the source of the problem but reported that the car was working fine and gave it back to me. The second time was a 10/1/2024. I was able to drive slowly to a parking lot, turn the car off, wait a bit and turn it back on which seemed to reset the warnings. Car is currently at a different dealer and they tell me that unless it happens while they are in the car, they cannot diagnose anything. If this were to happen while driving, it could be very dangerous as the Hummer is a very large heavy vehicle so to lose driving systems in motion is quite a scary thing. Having it happen while stopped is bad since the car doesn't operate normally, steering is erratic and the suspension controls non-existent which impacts safety even with speed limited to 36. The car is available to be inspected as needed.