The windshield and the side windows of my new 2010 GMC Sierra 1500 wt, have an extreme tendency to fog over in temperatures near the freezing point. I have read, and observed, that the ac compressor becomes automatically disabled when the outside temperature gets near the freeze zone (I think the actual threshold is somewhere around 40 degrees F). With the ac disabled, the defrost mode cannot keep the windows clear. The problem is magnified when there are two or three individuals in the cab. At that point, it is exceedingly difficult to clear the side windows, even to the point that frost forms on the inside window surface! very recently, while traveling to work during my 40 mile commute, I was running the ac, with the temp control set to a comfortable level and the blower about the medium setting and flowing through the main vents. The outside temperature was, apparently, hovering near the point where the electronics disable the compressor. The windshield and both side windows fogged over suddenly. I noticed the ac light was out, so I switched to defrost mode and hi blower. The windshield did clear in about a minute or two, but all of that happened while driving down the turnpike at 70 mph. This seems to be a significant safety concern....at least for me and my family. If the ac compressor had stayed enabled, this would never have happened. It is very difficult to stop condensation buildup if you cannot run the ac to dry the cabin air. This design configuration seems to present an issue of safety. I am not sure if it is just this particular model. I suspect so, since it is the base model truck. We have a 2011 GMC terrain, which does not present this issue. I have contacted the dealer about this issue now for 3 years with no resolution. They act as though you are an idiot.

- Berea, KY, USA