Where is the wire to the left that the second wire from the light is attached to?

sorry I posted this twice by mistake.

Just to clear it up, this is a RPM activated switch to make a LED light go on at the given rpm. I have a 98 civic EX. Sorry for the blurry pic, I dont have a scanner, just a camera.

Does anybody know, This scematic shows that there are two wires from the stock tach, the lead signal and a +12v wire, wheres this one?