Silverado dissolves itself

Man... I hope you get it figured out. My first thought was a nearby thermal window as some others have said. On my own house my living room extents out from the rest of the house by about three feet or so. Beside that room is a south facing family room with these newer double pane thermal windows. During the past summer I noticed that the sunlight from one of these windows is being reflected at a 45 degree (+\-) angle several feet away up against the vinyl siding on the part of the living room that juts out. And this one section of siding is being melted slowly. In a few more years I'm sure I'll have to replace it. In news reports I've seen on television you can see where the light from one persons house is being reflected against and melting the siding on their next door neighbors house. Sorry to beat a dead horse but don't discount the theory if you park the side of the vehicle being damaged where it might catch this kind of reflection. And... In any case good luck and best wishes.