I have a 96 blazer 4door with an auto tranny. I want to install a tach and replace the gauges with an indiglo one. they only make the indiglo ones for manual trannys so i figured what the hell why not do it up. so im gonna have to get new gauges out of a 96 manual tranny, and im gonna have to wire the tach, how do i go about wiring the tach?