I have a 2008 Big Horn 5er that has 2 window units that are all fogged up, obviously from loss of seal between the two panes. Has anyone tried replacing the glass itself or the whole frame including the glass? I called Heartland several months ago, explaining the situation, and they said the whole frame - containing 3 separate panes - would need to be replaced. Do you think this could be a DIY project if I were to order what's needed? Any and all comments are appreciated!