The contact owns a 2017 GMC Sierra. The contact stated that while his wife was driving at an undisclosed speed with the defroster activated, a smoke odor was detected inside the vehicle. The contact's wife checked the rearview mirror and saw flames coming from the rear windshield. The contact's wife pulled over and heard a loud explosion from the rear windshield shattering before turning off the vehicle. The flames from the rear windshield were extinguished on their own after the vehicle was turned off. There were no injuries sustained. The vehicle was restarted, and the contact's wife deactivated the defroster before driving to work. The vehicle was taken to the dealer, where it was determined that the rear windshield needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but informed the contact that there was no recall associated with the VIN. The failure mileage was approximately 97,000.