Dynamo wiring 2
 

Hey guys
So I just managed to connect my bottle dynamo(2 terminal, ground and plus) to my front light(single terminal) and it works. I did this by connecting the plus terminal on the dynamo to the front light, and the ground terminal on the dynamo to the frame. When I try to do the same for the single terminal tail light(by attaching the plus on the dynamo to the tail light) only the front light works. Any ideas?

are you sure your taillight only has one wire? The picture looks like it has two, possibly inside a outer jacket. http://www.bikeforums.net/electronic...mo-wiring.html

If it does have just one wire, it probably isn't grounded well enough to the frame. Run a second wire back to the light attachment point to see if it lights

If the lights are single terminal, it means tha they are likely grounding through the bolt to connect them to the frame. If the bolt hole has copper around/inside it, then that is what its trying to do. If the bolt hole doesn't look to have any ground connections, there is probably a second terminal you haven't found yet. I agree that your problem here is poor ground.