Ist time using defrost when snowing in November of 2009 windshield iced up and defrost unable to melt creating dangerous visibility condition. I took to dealer and was told that it was normal. I figured they woulld of had a fix for this by now, again this year same happened at 1st snowfall and again dealer told me the vehicle should be run for at least 1/2 hour before driving in snowy conditions which is contrary to idling laws currently being worked on. The heat is overwhelming coming out of defrost vent but very little hits windshield and wiper blades remain frozen all the time if vehicle is not parked indoors in heated area. I've had many GM products in the past but have never had this sort of problem.