For mine, there was 4 wires to hook up. The power and ground wire, which you can just hook on your battery. Then the one to light up the tach, you can put that somewhere in the fuse box, I put mine in my parking lights. Then the other wire actually tells you your RPM's. I think it was my Throttle Position Sensor (TPS) that I had to splice into. Maybe it was something different...but yea, it didn't come with instructions? //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif