I have a 2005 Night train, it has a 3 wire set-up for the front headlight. A low beam-high beam-ground wire. The aftermarket headlight I got from ebay is a 2 wire set-up, NO visible black ground wire. Is it grounded inside the headlight? Do I need to run the ground wire on my bike somewhere? Thanks for the help.. Is it safe to just run the 2 wires and not use my stock ground wire?

 

It may ground o-k when bolted up, but might not. Check the new lamp and see if there is a grounding tab on it anywhere to add the existing ground wire to.

 

You may have to run a ground wire.

 

While it should ground itself through its mount, it's a good idea to run a separate ground wire. Never liked the thought of the headlight current having to pass through my neck bearings, especially since they're greased up.

 

The theory is that it is supposed to ground through the frame,It, not a bad idea to run a ground just to make you sleep better

 

I've never heard of anything like this; if you have the 3-wire bulb, it's usually hi/low beam bulb, if it's 2 wire, it's hi-beam or low beam only bulb; they are not interchangable; maybe what you have is something different????? I'd like to know if it works properly.

 

I've got an aftermarket headlight on my Sloptail. It's 2 wire; 1 for hi, 1 for lo. Actually, thinking back on all the bikes I've put a custom headlight on, I can't remember one that wasn't 2 wire.

 

Skip, I stand corrected on this; after giving it some thought (seems you stirred up some memory cells), my jap bikes had 2 wires for the headlight connection also (I'm still thinking automotive too much, that why when I post an answer, if I'm not certain, I usually leave it open for a reply to find out how something worked or didn't)
thks,
Jim