Hi everyone,

I have been trying to figure out why my taillight isn't working on my 1993 xlh1200 Sportster. I removed my taillight and inspected my wires, which seemed all fine. I touched my bulb to the wires in the socket and attached my own grounding wire from the outside of the bulb to a known ground and the bulb lit. That leads me to believe it is my grounding in the taillight assembly. From what I have read the assembly should be self-grounding through the fender.

What are your guys' advice on next steps if the self-grounding is not working as expected? Can I clean the holes where the bolts go through to try to ensure a solid connection?

Thanks for any help,
Jake

 

Is there a wire from the headlight socket to the body of the taillight that should be acting as the ground? If so, you can splice onto this and run it to a good ground on the frame.

 

No, there is no wire from the tail light to anywhere in terms of ground. There are two wires that go from under the seat, along the inside of the fender and connect to the light socket. Those two are my running light and brake light.

I am considering just connecting a wire, using a ring terminal around the taillight assembly bolts, and connect it to a known ground on the frame. That seems to be my most straightforward and a guaranteed fix.

I have a continuity tester and I cannot find anywhere on the rear fender that is grounded. What confuses me though is that my taillight has worked in the past, like yesterday it was working intermittently.

 

That is the best fix.

 

I got a new ground wire ran from the taillight assembly to an area I was planning on grounding it to, but had not actually connected it to frame yet. After reinstalling the assembly, I turned on the ignition and the light started working again. Then I touched my ground cable to where I was going to attach it to the frame and my light became quite a bit brighter. It appears the self-grounding is working, for now, but is not doing as good of a job as having a dedicated ground cable.

I finished routing my new ground cable and attaching it, and am planning on keeping that from now on.

Thanks for everyone's advice on this!
Jake