Dyno Light Problem
 

My wife's SP hub is putting out power but the light does not work . I get a "flash" now and then. I do get continuity through the system.
Here is a pic. Not sure if this will help.
But help would be great!

As with many things, work to isolate the problem. Remove the wires and put them back. Put a multimeter on the wires to see if there is voltage. It is A/C. I'm not sure how, but it might help to try powering the light with a battery even though that is DC. The wiring for that test can be tricky. You should also use the multimeter to test for continuity between ends of each wire.

I have tested dyno powered lights with a Li Ion battery at near 4 volts DC, depending on state of charge. Have also tested dyno powered lights with USB-A power at 5 volts DC. If I recall correctly, B&M sells a light tester that operates at 6 volts.

You might be able to test it with a higher voltage source, like a 9 volt battery but since only the headlight and not the taillight has overvoltage protection, I would only try low voltage (6v or less) testing on taillights. Supernova taillights work different than the others, what I said might not apply to that brand.

If it does not work with one of the various ways to test it that I or NoGlider suggested, I suspect it is toast unless you are skilled with electronics.

If I recall correctly, you went on a bike tour to Europe, are you back here or still there?

Fixed! I took everything apart and put it all back together and it works!

That has happened to me with other things. On one hand, it's a happy ending. On the other hand, it's disconcerting not knowing what the problem was.