Help with hub powered headlight
 

Hi, First time poster here. I have a Velorbis scrap deluxe which came with a lumotec hub powered headlight and tail light. The headlight stopped working so I ordered a new one I hooked it up and it works fine until I touch it to the mounting bracket. It then shorts out. It's driving me nuts. Anyone have any advice? Here's a pic of the light and bracket. The tabs are for the tail light which also work until it touches the mounting bracket.

OK It wont let me post pics until I get 10 posts.

Lumotec headlight.

you have the wires swapped somewhere along the way from the hub to the light. What brand hub is it? Many hubs have the ground shorted to the frame, and that's what I think is happening with yours. You can probably just swap the wires at the headlight.

I'm assuming you don't have a taillight. That is another path to ground

Agree with Unterhausen, but trying to add some clarity here.

If your headlight is the one I think it is, the headlamp is grounded to the frame and it has the wires attached to the light.

I assume it is a Shimano hub. If so, the little plastic connector with the wires that attaches to the hub is in two parts, you have to take it apart, switch the wires, reassemble.

Try it first without the taillight to see if the headlight works by itself.

Then if it works, add the taillight. If adding the taillight makes both lights stop working, switch the taillight wires.

If this does not fix it, we need better description of what you have including brand and model hub.

Well hot damn that worked. I thought I tried every different combo but just switching the two wires did the trick. BTW, It's a Sturney Archer hub and Lumotec headlight tail light combo.
Thanks again boys. I rarely ride at night but like to keep my things in working order.

Thanks for checking back in

Yes I hate when there's no follow up to good advice. Now, maybe it will help someone else.

My first two dynohub setups used a SP hub. That hub is not grounded to the fork. So, the third time I put together a lighting system I was stumped for hours trying to figure out why the Shimano hub was not working out. And since I already had set up two bikes with dynohubs, I of course knew it all. I eventually figured out that the Shimano hub was grounded to the fork and so was my headlamp, thus switching the wires fixed it.

And, a couple months ago I changed headlamps on a bike, did not hook up the taillight until I was sure that the headlight was working, and headlight was intermittent. Then finally figured out that the taillight wiring that I had not hooked up yet was occasionally touching the contacts and shorting out all the power. It is amazing how something as simple as these lighting systems can be so troublesome.

I was unaware that Sturmey Archer still made dynohubs, I do not think I have seen one for a couple decades, I learned something from you too.