Wiring help please

Ian, this is no job for beginners. Not only do you need the correct color wires, you need the right gauge wires, proper connectors and wrapping. You could unwrap what you have and inspect it, then replace any wire found melted or missing insulation with identical stuff. You will need the correct blade fittings and crimper. You'll also want to solder all crimped connections as well.

If you must unwrap the entire harness, I recommend laying it out on a plywood panel and tracing out the bundles onto it before taking off the wire wrappings. Annotate where the splits are too, so when you are rewrapping, you'll get it right. Buy some of the non-adhesive tape too to match the original. Clean all reused end terminals and coat with dielectric grease before reassembly.

Take your time to get it right. Good luck!