Replacement wiring harness
Rebuilding your harness isn't rocket surgery.
Pull the harness out and lay it on a piece of plywood. Separate it all out and outline it with finishing nails. Unwrap and start replacing/repairing one wire at a time. If you spend a little time figuring it out, you can add additional circuits that you'll need.
Here's a wiring harness I was working on for a 53 Chrysler Windsor.
BTW, this is the method used to build short run production harnesses. I've seen this used for military electronics.