For those of you that do this regularly, I'm sure this is obvious. But for me, it was an interesting learning opportunity:
The wires for the taillights in my speedway motors harness are yellow, green, and brown. Yellow for left stop and turn, green for right stop and turn, and brown for running lights.
For anyone who has ever had to wire trailer lights, the color scheme is the same! So if you have done one, the same applies to the other.
Hope this helps someone else new to car wiring like me!