Hey, have you fixed this one yet? Personally, I'd recommend against trying to do it with the windlass still fully assembled. To get proper access to the contactor and the wiring, you're really going to need to take the top off and lift the motor or gearbox assembly out of the base. If you try to do it in its original place, you can risk damaging other wires or the seals, which would just lead to more problems.
If you're considering my suggestion, just take your time, get a good diagram for reference, and make sure you label everything as you disconnect it! Good luck! Let us know how it goes!