weltertm,
Of the three terminals on the back of the ignition, one goes to the - side of the ammeter. This is the wire that will power the switch.
Another terminal goes to the coil + and also to the fuel gauge.
I don't believe the third terminal is used.
Is the wiring diagram I linked any more clear than the one you have. Wire size is important in this equation, and these are shown on the schematic.
Stuart
