2025 GMC Sierra electrical system problems

“Repeated failures on my 2025 GMC Sierra EV. The truck shows 'Service High Voltage Battery' and the high voltage battery makes a high-pitched hissing noise; it has thrown battery errors twice. The A/C has failed repeatedly; this summer a passenger in the truck overheated and suffered heat stroke because the A/C was not working. Super Cruise and other driver safety features consistently fail while driving. The GPS/telematics module has failed (GPS never finds a location). The truck was at Bob Howard GMC in Edmond, OK from [XXX] to [XXX] (repair order [XXX], 41 days) for the telematics module and A/C, and went back on [XXX] for the A/C and battery and is still in the shop. GM case number [XXX]. No crashes.”

“The engine locked up and stalled out while driving. GM replaced engine but still experiencing issues. Dealer has admitted that they will likely recall my model year since it is an ongoing and same issues as recalled trucks. I have a vehicle I am not confident in nor safe it since it stalled while driving.”

“The contact owns a 2025 GMC Sierra 1500. The contact stated that while driving approximately 5 - 10 MPH, the vehicle went into LIMP Mode and failed to properly accelerate, and the transmission unexpectedly downshifted. There was an electrical malfunction, which caused the transmission to downshift. An unknown message was displayed on the instrument panel. The contact stated that the network was not operating at the correct voltage due to the wiring harness. The engine light illuminated after the failure. The vehicle was towed on two occasions to the dealer to attempt to duplicate the failure. The dealer was unable to determine how to repair the vehicle. The vehicle was driven to the dealer in LIMP Mode. The manufacturer, General Motors, was contacted by the dealer, and the contact also reported the failure to the manufacturer. A General Motors service engineer had inspected the vehicle. The failure mileage was approximately 34,637.”

“When updating the vehicle as prompted by the entrainment system the next day when attempting to start the vehicle it did not start. Vehicle had to be jumped then 6 warning lights came on and disappeared shortly after driving.”

“I pulled up to a local store and parked. Just as I was getting out I saw smoke coming from the upper seatbelt area of the rear drivers side seat inside the cab. I jumped in back to see if there was a fire. As I was trying to pull out the top cushions of the interior roof, trying to locate a possible fire, the rear driver-side window suddenly "exploded" - broke in a web pattern across the entire window. I then broke out the center of the glass in case a fire started. I could smell a burning scent. The, suddenly the rear passenger-side window exploded in the same web pattern across that entire window. When my wife arrived to pick me up she could also smell the scent of burning wire. After researching the internet for this issue, we found out that this is a known issue. We discovered at least 6 websites describing this exact issue - one being a GM Customer Satisfaction Program #N192265660 dated January 2020. Apparently the component that has been determined to have failed is the rear window defrost (particularly in models with an electronic sliding rear center window) overheats and causes the smoke and the window breakage. After our truck being at the dealership…”

“The truck when put in parking it still roll forward a little bit. Back up camera can’t not see during night time. Dealership stated they will not solve that problem and tell us to do manually by turn around look back. The suspension really bouncy but the tech stated that is normal. Spoke to other 3rd party tech they said that not normal at all.”