Am I correct to assume that the alternator only requires ground (alternator body) and positive (terminal B to battery) to function? ie: put out power to battery. And the plug on the rear of the alternator is acc wiring (ign, lights etc.).

 

No, the plug on the back with the 3 wires have specific placements. Depends on which plug you have to determine which wire, but one must be to ING+, and one must be to BATT+. Failure to connect those will result in the alternator not charging the battery.

 

IC. So if I were to throw a toggle switch on the ing+ to the battery, and wire the other inline to battery+ the battery would charge? (Assuming that I have the correct wires.)

I am doing major modifications to a salvaged/wrecked SC400.