I watched the folks at Suncoast Designers in Hudson, FL repair our fogged windows. Removing and replacing a window isn't hard, but you will need one very strong person or 2 normal people on ladders outside the front passenger to lower it to the ground. Tiffin uses 1/4" glass, and the big cockpit windows are very heavy.
Trim the silicone sealant around the outside of the window with a sharp knife being careful not to scratch the surface of the fiberglass or paint. Then from the inside, remove the valence, remove the screws around the black aluminum frame and push out on the top of the window while those on the outside hold onto the window.
To replace, reverse the procedure. The window is sealed by a rubber gasket on the outside frame that presses up against the outside of the motorhome. The bead of silicone is a secondary seal for insurance.
BTW, repair by Suncoast or by any one of several other RV window repair houses is a less expensive way to get rid of the fog than replacing the windows. Suncoast charges $275 to repair and reseal cockpit windows and $225 for most of the rest. There is a 10-year, pro-rated warranty.
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