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wiring question converting 24 volt JD 4020 to12 volt system

Howard Childress Hoss gave me the solution to my fuel gauge question(problem) but I have encountered another problem.
How do I get the charging light to work? It has a one wire self igniting alternator (12 volt).
The charge light will come on showing the battery charging but won't go off. I have added an amp meter that works but what could I have done to get the light to work properly..? I hated to bore a hole in the dash for the amp meter but didn't know what else to do.. Your advice and response appreciated. Howard

Howard Childress John Deere 4020 alternator light problem
I just reread what I posted previously and realized I didn't proof read it before I posted it.
What I meant to say was that it had a 12 volt self-exciting alternator not self igniting...
I sure hope it's not self igniting..
Any way it's a one wire alternator and when I start the tractor the idiot light comes on but won't ever go off.. Do I have to have a relay or something or can I fix it an easier way?

Hoss The charge light must be shorted to ground some where. Your one wire alternator has no place for the light wire to be hooked up. So if your light is staying on the wire from it must be shorted to ground because it isn't hooked to the alternator.
Howard Childress Hoss, thanks for your help. Exactly how do I wire the idiot light so that it comes on when the switch is turned but goes back out when the alternator is excited or starts charging? Thanks again for your help and advice. Howard
Hoss With only a one wire alternator you can't. If you had a regular delco with built in regulator you just hook the light wire to the #1 or R terminal and jump a wire from the large post to the #2 or F terminal.
Don DeBoer The alternator light on my 64 4020 won't shut off sometimes when I shut the tractor off. I put a new light switch on the tractor and that seemed to help, but now the same thing started again. What other things should I try.

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