Yep, this sounds like a nightmare for sure. Based on what you described, I think you're going to have to check just about every wire for damage. BBB Industries - TSB's & Wiring Diagrams has online wiring diagrams, and IMO at the very least, you'll need to check for end-to-end continuity. Hopefully you won't need to unwrap lots of bundles, but it's easy to imagine that being required as well, because there's no way to know what's melted and what isn't. And hopefully along the way you'll also figure out what's the originating culprit for all of this mess. Best of luck with this!