This light bar needs rewired. The spotlights come on with the key as wired now . That means they will pull on the battery when you are trying to start the bike. I would bet it's tapped into marker lights with a scotch lock, too. That's bad because it could come loose and if you want to replace the 25 watt lights with 50 watt lights you will pop fuse. 25 watt lights are really a trick to come by.
I really don't like how this is routed with no shrinkwrap either.
Here's the tap.
Not a scotch lock, but I'm still going to move it.
This is the best way to wire a light bar on 1500/1600 Vulcan. The Aux circuit gives you a 10 amp fuse. Tapping the blue/yellow headlight turn-on wire, means the lights won't come on until the motor runs. The lighted switch means you can turn them off if you want and see if there's power to the switch.
Build a two wire harness to go from the Aux lead and ground lead that are under the tank. (Those are in the headlight bucket on a 1600.)
I didn't get pictures of the wires from the switch side, but you need 4 wires when using a lighted switch. One to the spotlight itself, one for each side of the switch, and ground to make the light of switch work.
I used a square relay I had on hand, and I discovered that had to clearance the headlight backing to fit everything.
Last time I used a Pilot Brand with Molex Socket relay it's smaller and fits fine.
The worst part of this project is that I won't be able to test it until I get antifreeze back into the engine and a fuel tank back on it and then fire it off.