I bought this 2005 GMC Envoy for everyday driving. I live in Northern IL and its real cold this Winter. I have yet to scrape my windshield this year. Is there a reason why every morning I wake up to a clear windshield ? Any my previous cars/truck, I would have to scrape the windows before I drove in the morning. Is there a trick or a product that prevents iced up windshields in the morning ?? Thanks !!