While driving the vehicle I turned the rear window defrosted on. The rear window started smoking after 5 minutes of turning on rear defroster and filled the vehicle cabin with smoke. I immediately turned the rear defroster off and pulled off the side of the road and opened all the doors to air it out. I then went back in and turned the defroster back on to verify the rear window defroster was the issue. It instantly started smoking again and was scalding to the touch of the bottom right of the sliding window. I turned defroster off and waited about 20 minutes where I felt that it had cooled. After some research I found the TSB provided by GM. TSB # N192265660. I contacted GM customer service and they said there is nothing they can do and it will need to be fixed out of pocket. This is unacceptable as this may cause the window to blow out on passengers, or can cause a smoke inhalation issues. I had everything I could do the get the vehicle pulled over because I could not see. The truck is only has 56,000 miles on it.