Side window fogged up.

It is very much a do-it-yourself project. I found that totally separating the two panes is unnecessary. After wasting time that way, I found it was far easier and quicker to cut out the top and bottom spacer with a razor knife and using a couple of wire coat hangers to pull a cleaning rag back and forth between the two pieces of glass. Use white polishing compound as a cleaner. If you completely separate the 2 panes, re-alignment can be a problem and you have to wait a day or two for the sealer to cure to reassemble the window unit. Leaving the two pieces attached on the sides lets you do the job in one day and generally one side has an aluminum strip pressed on with the lock although you should also pull that off to allow you to apply a fresh coat of sealer all the way around the window. Search on Amazon for 'super spacer' and '877 sealant'. Be sure to get the correct width spacer. You will save a LOT of money doing it yourself. Do it on a dry day and you will be good for anther 10 years. "Lifetime warranties" don't mean much since it's unlikely you will keep it another 10 years. It does requires removing and disassembling the window assembly on the RV.