2020 GMC Terrain electrical system problems

“The back passenger seat exploded and caught fire, burning the back of the seat in front and burning the ceilings. Inside the whole vehicle is black from smoke damage. Incident assessed by fire marshal who has ruled as electrical issue. No warning lights or systems displayed anything.”

“The contact owns a 2020 GMC Terrain. The contact stated that while driving in cold weather at various speeds; moisture accumulated and deactivated the charger, causing the vehicle to go into LIMP Mode and lose drive power. The vehicle was taken to the dealer, who diagnosed the vehicle and determined that the charger air cooler was defective and needed to be replaced. The dealer also wanted to place an air deflector on the vehicle. The contact was informed of a service update for the failure however, the VIN was not included. The vehicle was not repaired. The contact researched and learned that in Canada, the issue was being remedied with a bra apparatus and a thermal wrap for the engine to prevent the failure. The manufacturer was made aware of the issue and confirmed that the VIN was not covered. The contact was waiting to hear from a supervisor. The failure mileage was approximately 140,000. The VIN was unavailable.”

“Towards the tail end of a nearly 2.5 hour drive, the Automatic Theft Deterrent System was activated on the interstate. I lost every display on the dash panel including my speedometer, battery, coolant, gas, turn signals, and windshield wipers. I went into the nearest parking lot and was unable to restart the vehicle. It was towed to the dealership closest to our home and was repaired for $2200. The technicians at the dealership were not sure of what caused it and had never seen an issue like this so it was “elevated” to the GM engineers at their headquarters. They replaced the electrical control module and both key FOBs. We have not experienced any similar issues.”

“My a/c went out within 2 years of having the car in 22’. In 2025 i have had nothing but problems, the radio will go out when im driving for about 2 hours and it resets, the screen goes black, music stops, navigation stops and then it turns on like nothing happened. It happens everytime I drive 2+ hours. Back in September of 2025, I was on my way to work when I was stopped at a red light, it turned green and then my brakes locked up and I couldn’t drive my car had shut off, and wouldn’t come back on. I was stuck in the middle of the road not knowing what happened as the car had driven fine up until i stopped at the red light. Then tonight November 21,2025 around 0315 I was leaving work, I started my car, my car threw up a message that said “Low fuel, 0 miles” I had half a tank of gas when I got to work. I turned my car off then back again and it did the same thing. I let my car sit for a second and then my Gas gauge started to slowly increase to the correct amount of gas. Then when I got home (3 mile drive from work) I turned my car off and then back on and this time when I turned the car on my brakes were locked and I couldn’t start my car. All of the Engine…”

“Break assist light comes on and brakes stiffen suddenly with no warning. Happened 6 times now in a 3 year span. Gotten it "fixed" each time but it keeps happening”

“[XXX] once again while diving down the road 45mph Terrain once again goes in to park ,I was lucky the lady behind me wasn't to close .Also I contacted onstar when I was able to get vehicle moving at the store ..I told her what happen she ran diagnostics while parked at store said there was no codes I let onstar know this has happened several times..I had no warning, no indication, no lights came on.And I also let her know that this same vehicle was still stalling I was at intersection and the auto/stop is always on it will not let you bypass or default took it to dealership who I bought CPO back when it first would not let me turn it off cause its stalls at stop signs ,red lights etc crazy thing is if you turn the ac on it cranks up , if you hit the door unlock it starts... Thats not normal GMC knows that the dealership whom sold me CPO that wasn't the misleading is beyond crazy..GSM cussed me out It comes with life time warranty but when I had it towed right after I bought it 2 months ..I was talking about what the mechanics had said that this vehicle was in prior flood and accident GMC onstar has a different Vin then the one that on the vehicle..The doors are…”