Electrical help needed, underdash wiring is a disaster

Many ways to go, depends on budget, how original you want it, what your skill level/ physical condition, on and on

1....Find a used OEM harness

2....Buy a generic "12 circuit" harness Some of these are quite budget priced

2....Buy a generic harness/ or just fuse box and pull out and patch up what you have now. "Not that hard" Pull it out of the car, spread it out on a bench or plywood, and tape and nail down all the branches, and untape it. Repair/ replace on a wire by wire basis. The connector shells are mostly reuseable, and they mostly use what are called "Packard 56" terminals.