There are a couple different ways. You need to tap into a constant 12 volt power source, a switched power source and a ground. For the constant power I tapped into the hot cable behing the cover on the fire wal. The ground that one should be easy. For the switched power I ran more wireing to a side marker light, that way when the parking lights are on the angel eyes will come on too. A word of advice: keep that relay from moisture I have a prob will the relay getting corrosion and causing intermittent operation. Hopefully that helps.