First off, thanks for all the help. Great Forum!
So the only non-functioning thing left on the Puch Maxi is the taillight (the running light, not the brakelight.)
At idle I see about 4 to 5 AC volts in the bulb socket. But when I put a known good bulb in the socket it doesn't light. So I figured I may have bad contacts in the socket. I cleaned the contacts and gave them a little extra bend to insure good metal-to-metal contact with the bulb but got the same results.
So next I actively monitored the 4-ish volts going to the socket and I found that as soon as the bulb is inserted the voltage at the socket goes to zero.
As I sit here thinking about it, either the coil used to generate power for the taillight has a problem, or the gray wire-to-gray wire connector block is so highly resistive that it looks okay when the bulb is out but when the bulb goes in the voltage drops across the terminal block instead of the bulb filament.
Is there something else I should be looking at?
I can pull out the gray wires out of the block and twist them together to make a no-resistance connection, but what if it seems that the coil is bad. Is this a difficult thing to replace?
If the coil is bad, I am thinking to parallel the taillight off the yellow horn power wire. The horn works so I know that coil can delivery power and the horn is rarely used. Does anyone know of a reason why that would be inadvisable?