Tach Wiring

[RAY WYGONIK <RWYGONIK@grove.iup.edu>]

Thank god for this list.  

I am installing the tach and find I have one more connection on the tach than I 
have wires.  None of the wiring diagrams I have even show more than a 
ground(black) wire and a green wire.  

There is a white/black wire that has a female connection that mated up with 
one of the extra terminals.  There is one more terminal with no available wire.
  
Anybody know the color of wire for this terminal and it's origin?