I'm pulling off my signals on my 03 night train and putting a fl touring light bar on, problem I have is the light bar is 2 wire and the original wiring for the signals are 3 wire, I believe the ground is internal in the light bar, my question is do I just cap off the ground wire coming from the bikes wiring?

 

Hi
my advise is to get (screw or solder) a ground wire from the light bar, as close as possible to one (or both) lamps and hook this wire to a ground wire in your cable loom. I would not trust the chassis grounding, they become unreliable after a while due to corrosion.
Nick