Just a quote thanks to Nate of the 5United group to begin with:
Actually the wiring numbers codes are a strict DIN standard ... # 15 is always unfused ignition current so your green coil feed goes there , # 56 will be the headlight current between the ign. switch and the dimmer switch , # 56a is the white high beam circut #56b is the yellow low beam circut # 58 is the taillight circut. # 30 is unfused hot + from the battery and is ALWAYS red , # 31 is ground and is brown. # 31b will be a switched ground , like the button side of the horn circut and will usually be brown with a white tracer to indicate it's a switched ground circut. it's all pretty simple and is on the Internet somewhere ...
Pictures are courtesy of slash2nut of http://groups.yahoo.com/group/5united/
Diagrams are courtesy of nsgreear of http://groups.yahoo.com/group/5united/