I started my car after work, I did not turn on the defrost fan for about 15 minutes cause I was on the phone. It was -6 degrees celcius outside, when I finished phone call I turned on defrost full blast at hottest setting. I left my work parking lot shifted into 2nd gear got up to about 25km/hr was about to shift to 3rd when I heard a really loud bang, louder then anything normal. I pulled over and checked my car and found rear window in a million little pieces. Took to the Ford dealer told them the story gave them pictures and they refused warranty. I know my car, it had not been long since I last walked around it, and there were no rock chips also last winter I went out to start car and I noticed rear window looked deformed pushed up in one spot, at the time a attributed this to my imagination and nothing bad happened until now. I would not recommend buying a Ford as they don't honour there warranty to me the glass was flawed from factory I believe this cause of the way it exploded and it is not easy to get a rock chip or impact on your rear window.