|Jim McVay said: (quoted from post at 11:33:15 01/03/10) If you have a alternator that needs a wire from the switch to charge it will not shut-off with out a way to isolate the two. I use a key switch with the coil wire on the ignition terminal and the alt wire to the accesory terminal. It works good that way. There are other ways to do it with a diode also.|
IF you are referring to the typical Delco integral regulator type alternator it should not be wired this way. The reason for the idiot light/ resistor, or diode is so that NO current can ever flow back through the no1 (exciter) terminal---which is trying to be supplied by the tiny diode trio. This can happen with a health alternator, for example, if for some reason the main output drops and the trio tries to become the source.
Sometimes yhou can "pop" a diode trio the first time you fire it, and some of them will go years. You really SHOULD HAVE a diode or resistor in the no1 lead.
So far as wiring the coil----depends on the ground polarity. If it's 6V pos ground, the coil needs to be reversed, too.