Not too old of a thread, but I'm having the same issue with my alternator. I've replaced all the alt to reg wiring with 14-16 gauge that have individual spade connectors on them, but it doesn't work. I took the alt off and sanded the grounding connections and tested (1 ohm) I've got a 6 gauge ground on the front of the engine connecting to the frame and battery terminal, the rear one to the firewall is something less but its still as low as my multimeter can read. Anyway pretty sure the ground is connected.
I only have the FSA terminals connected.

I have a second alternator that I had previously connected, but I was using the original slightly hacked up harness. I didn't get to use the new harness with that alternator because a stud unscrewed, leaving a loose nut inside the housing. I took it apart and ended up cracking one of the contact magnets that rides on the center shaft. The alternator is made by Tuff Stuff, which BTW has horrible non-responsive customer service. Anyway does anyone know if I can purchase a different magnet lead or if I have to use the original piece? All it consist of is a magnet that is cast with a copper lead inside.