Classic/Antique Car Repair: Headlights, good luck jack, berlin ohio

Question
Just finished rebuilding my 1930 Ford A model.
Headlight will only burn when engine is running. I have a working 6v generator with a new style diode cutout. Any suggestion on the fix.
Thank you

Answer
The cutout should be OK, but I think it is a wiring problem.
Check to make sure you have fire at both sides of the coil with the key off.  If you don't, then fix it.
If you do, then check if you have fire at both terminals of the ammeter.  If that is OK, then check the yellow w/black stripe wire from the terminal box to the gen.  It should be hot all the time.  Maybe the cutout is wired backwards???  Check that.
Try all that and get back to me.  I'm going on a Model A tour for most of next week, (Berlin, Ohio.
Be back the week after.
Good luck
jack