[CharleyL]

You will need to locate a wiring diagram for your cart. You can also try to look the full length of the harness to see where those wire colors exit at their other end. When you think you have found the other ends, do a continuity check with a multimeter to be certain that it's the same wire. Where it is connected at that end should give you some idea of where it should go at the relay end. Do the same with all three wires. A wiring diagram shows the colors of wire and all of the connections. With the diagram you save a lot of time, but when one isn't available, the other method is what I have described.
I've never worked, or even ridden in a Yamaha, so can't provide any other help. Good luck.

Charley