I've bought and installed dynamo powered lights on my bike. A little bit about the setup - It's the bottle dynamo kind pressing against the tire system. The Dynamo produces current turning clockwise and counterclockwise. The setup completes the electrical circuit using the frame of the bike. The front and the back light are powered by the same dynamo but are wired through separate circuits.
I've set up and used the system successfully. However I was doing some work on the bike and had to dismantle and reattach the front light. From the moment i attached the front light back the system hasn't worked. If i disconnect electrical influx and the return loop from the front light the back light works. If I connect merely the influx connector the back light works again. In other words - the entire system stops working when the front light is connected fully and properly in the manner that the electrical loop / circuit is closed.
I've tried using a backup front light with same results. The bulb, even if it were out on both of the front lights i tried, can't be the culprit - the back light should still work as it is wired to the same dynamo but independently. I've checked the influx / hot / live cable of the front light, it isn't damaged - but again, even if it were and it were to touch the naked bike body somewhere, the back light system should still work.
This is the only situation in which the entire system fails: When the front light is connected properly with the electrical in and out cables attached.
Which would mean that the entire system fails when the flow of electricity through the front light is established, not impeded - which makes no sense! In all other situations the back light works fine. So what the heck is going on?
I apologize for using improvised terminology (influx and such), I'm not an expert on electrical systems, as such the answer could be glaring however I don't see it.
I've checked previous threads with similar issues like this one Diagnosing faulty circuit in vintage incandescent headlamp however I've found no matching issue or applicable solution.