Regulator gone bad?

Well, that narrows it down quite a bit.

The battery charges straight from the alternator through the termnial at the starter relay. Good.

Your issue is someplace between the connection at the starter relay, and the fuse box. Since the ammeter bypass was done, all of the system power comes through the firewall on one wire.

Check the connections to the OEM fusible link. Check the link too - bend it gently, it should feel like a wire, not a hose full of gravel.

Check the connection at the red wire.

Pull the fuse box loose, and check all of the connections.


B.