wired it up using the factory wires under the dash. There is a 2 wire plug under the dash the red wire is to the coil and the green and read wire is hot with the ignition on. The tach has 4 wires. You wire it Green to the Red coil wire, Black to ground (I used the Brown ground wire for the clock), Red is hot for the tach and Blue it hot for the light I wired them both to the Green hot for the tach.
