Sorry, Roy- - - -the diagrams I've been able to find show the indicator light circuit, not the ammeter type. I know I've seem a factory original diagram for the ammeter, but I can't remember where- - - -possibly at one of the factory seminars I attended back when I was teaching electrical systems. There was a shunt involved that bled a small amount of current away from the main charge wire, as I recall.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!