As one of the nation’s first owners of General Motors’ new electric Chevrolet Blazer, James Hattin was loving the SUV—before the problems began.

On a trip from the mountains back to his home in Burbank, Calif., he and his wife heard weird clicking noises coming from the dashboard. A short time later, the cruise control went out. A few days after that, in his driveway, the car’s screens went blank and the car wouldn’t start.