A co-worker has a yamaha v-star and is putting a new taillight on. The original light had two wires in it and the new one has three. He's having a hard time figuring out where the third wire goes. It is an aftermarket light. Any ideas?

 

Does he have any kind of instructions that came with this light? What color or the wires?

 

The third wire is the ground. His stock light apparently grounded through the mount hardware.

 

...what he said...ground to fender, frame or possibly tailight housing if it's metal and it's bolted to fender in such a way that it will make ground.
Later

 

Thanks.