tachometer wires
 

I bought a used Sunpro II tach today cause I had an old cheap one that I didn't trust anymore.
Can someone help me out with where the wires go?
These are the color wires:

white
green
black
red

I know black is ground and one is the background light and the other two go to the coil. Can someone help me out?

Red = Power (found a "key on" power source in the fuese box)

Black = Ground

White = Tach illumination (I've got mine wired into the dimmer switch that way I can turn the illumintaion up and down with the stock gauges)

Green = Tach signal (Wire it into the negitive (I think???) side of the coil. Wire it onto the "tach out" port if you have a MSD box.)

You think correctly sir.

Thanks