Defroster/defogger/hvac System Rear Window problems of the 2015 GMC Sierra 1500

The contact owns a 2015 GMC sierra. The contact was informed by the dealer upon purchase of the vehicle that there were three recalls on the vehicle(recalls unknown). One of the recalls was related to the rear defroster which the dealer informed him was repaired. The contact stated that upon start of the vehicle he smelled an abnormal odor emitting from the vehicle. While traveling at 25 mph, the contact heard a popping sound emit from the vehicle but initially though nothing of it. The next day while driving the vehicle, the contact felt a rush of air entering the vehicle and upon inspection discovered that a baseball sized hole had formed on the back rear windshield. The dealer was initially notified of the failure but they offered no assistance. The manufacturer was also notified of the failure and referred him to a dealer for a diagnostic. The contact then took the vehicle to an independent mechanic where the windshield was replaced. The vehicle had been repaired. The failure mileage was approximately 30,000.