That's my guess anyway... My daughter's window is starting to act up now too just like yours. I haven't tried the lockout button but if it blows my fuse I'm going to be watching your post with great interest...
The switch comes out easy enough but getting to the wiring requires that you pull the console. it's not a big project just takes time and is easier without one seat in teh car. I can pull one out though in about 5 minutes. passenger's is easiest due to no arm rest.
Might also just try to see if you can find an open to ground wire from the rear switch. This might at least give you an idea what wire you're chasing.