the coil primary has a good chance of stoping with the points open so your bulb wouldn't necessarily be ON with ignition on.
however if you want a small light /or buzzer to be ON only when ignition is ON and engine is OFF you could connect the bulb or buzzer between ignition power and the GEN. / Armature post of the generator.
when the ignition is ON and engine OFF, the buzzer / light will sound because the generator is such a low impedance compared to the buzzer / light to ground that it would have basically full battery voltage.
when the generator is producing power, the shunt relay closes and your buzzer / light would have 0 volts across it.
-s
