Since the wiring on my buggy was quite bad when I ordered the new wiring harness some of it was a little difficult to follow, but I am pretty sure I have everything hooked up correctly except for the black and yellow wires with bullet connectors. I am pretty sure the black wire is intended to be a ground to the engine, but not at all sure about the yellow. Can you please give me some direction here.
Do you have a Yerf Dog, or a Crossfire?
In either case, the black and yellow bullet connectors can be left unconnected if you choose. They are for the running tail light of the CF150. If you have the Yerf, those hookups can be used to install your own tail light.
Here is the install guide image from the product listing that covers the rest of the connections: