Hi Brian!
So sorry to hear you're having trouble with your lighting setup. It seems the most common fault with dynamo systems relates to wiring and connectors, so I would check those first, looking for breaks and loose fittings. It is most likely you're using a double (in the case of Edelux, coaxial) wiring setup, so you wouldn't have to worry about a ground (earthing) fault caused by using one hot lead and the frame as the return.
I would suggest starting with the dynamo itself and see if it is producing electricity. If you have a voltage meter, connect it across the two terminals, give the wheel a spin, and see if anything registers. Lacking a meter, you can connect a bulb and see if it lights at all when moving the wheel.
I can't endorse it, but the SON hub will produce enough current to give a shock at the fingertips when they bridge the terminals while the wheel is spun briskly. That's one way to tell if it is working, but I have to caution against it even though I'm the guy who roughly tests the voltage in 9-volt batteries by placing the terminals against my tongue.
If the hub dyno is working, then the problem is likely in the wiring or the light. If it is the light, it might be in the magnetic switch. I have read isolated reports that can be a rare problem on the Edelux. If so, I recall seeing the part (ring-switch) available recently on a German vendor's site.
Hope this helps.
Best,
Dan.