I'm in the process of hooking up new LEDs. I'm assuming that I hook the yellow (auxiliary wire) to the tail (running lights) not the stop n turn? Please someone correct me if I'm wrong. Its a 1972 Boler.
It sounds like perhaps someone has replaced the original wiring with a trailer, off-the-shelf wiring kit. In the Document Center, at the left under Resources, there are two 1976 Boler manuals. Neither one shows a yellow wire but does insicate what circuits are in a Boler. As Roy said... Use a circuit tester, or a meter, to check your wiring. Then keep a list of what you have for future reference.