Originally Posted by
neondave
Do you have a MultiMeter for checking voltage/resistance ,etc ? If not ,Harbor Freight has cheap ones that work well for under $10.
Ive had light bulbs & fuses that appeard to be good that didnt work.
Can you hold the bulb in your fingers,& take the wire that goes to the headlamp and hold it against the thread on the bulb and touch the other contact against bare metal on the frame to see if it lights ?
Good luck, dave
Thanks for your reply!!
I do have a meter, though it would take me a while to figure out how to use it.
Using a known good flashlight bulb, I have checked the wire I'm using with a couple of D batteries. Good. (it's old wire, but no hidden breaks inside the housing)
Using same wire and same batteries, I have checked the bulb. It lights up.
Bulb and wire are good.
Also, testing without the taillight inline, just in case that could make a difference.
For some reason, when I install the good wire from the dynamo to the front light, using the good bulb, and run the wheel so that the dynamo goes, the bulb will not light. Doesn't matter if I'm touching the ground of the bulb to the chromed steel light bracket or have it actually installed in the socket. (I also reached inside the socket with a tiny screwdriver and pried the ground contact forward a little to make sure it was contacting the bulb.)
I'm running out of ideas. This can't be that complicated.