1998 Fatboy Tachometer wiring

[1988fbi]

I recently purchased a used 2.5" HD tachometer off Ebay. I was told it came off a 1998 Fatboy also. I wrongly assumed that it would come with at least a pigtial of wiring. WRONG!

Can anybody provide me with information as to how to wire this unit to my bike? There are 3 terminals inside the case, again assuming one is the ground wire. Looking at the back there are 2 terminats near each other that appear to me to be the feed lines, the one by itself I think is the ground terminal...,Anyone have information or a wiring diagram? and/or instructions as to where to hook these wires.

Thanks for any help you can provide.

Roger