After a small snow fall but wit some icing overnight i turned on the front andback warmers for the windows. as i travelled about 1/2 a mile i heard a "creaking noise" in the back of the vehicle, when i looked up i noticed a crack in the glass backk window and then continued to get bigger and bigger until the entire window was gone. i was told by the dealership that glass is not covered by the manu warranty. this was the first time i'd used the backwindow defroster, needless to say i'm not happ since i've only had my vehiccle since december 26th. i've attached to photos. my car is kept in my fenced in backyard.