So this is my story.
got the tach.
no instructions.
im f*cked..
the end



there is a black wire (ground) kay got that one
red (hot) got it
Green (signal) got it
red and black together (shift light) got it
then this damn wire two black wires together. WTF is it!

 

Some tachs come with wires you have to cut, so it can work right with 4, 6, and 8 cylinder engines. Are these the two black wires you speak of?

 

nah these wires go to the face of the tach w. the numbers on it

 

what kind of tach is it?? whatever brand it is go to their website, should show you instructions to hook it up. Or just use the tach in your gauge cluster and learn when to shift instead of having a annoying light in your eye when you need to shift

 

its the shift light loom plug

 

i got a jdm zc that has no limiter i rev out a 8000 and im noot trying to fuck my motor. there is no tach in the dash.. hense the aftermarket tach. it a apc tach and no the black wires dont go to the shift light...

 

its either the universal wires for the 6 or 8 cylinders or its either from the shift light. what else could it be? nothing that I know of

 

name brand of tach, we cant help much more without that or a pic atleast

 

I'll bet the two black wires are for the gauge illumination if they go to the gauge face. Light bulbs don't have a polarity.

 

i'll bet your right, I forgot about the white wire thats usually on there for this.