 Now, if you have an existing light fixture, hooking up a new motion detector fixture is really an easy project. First step, kill the power, right? Make sure it's off. Then you can remove the old unit and wire up a new one, and that's about it. The same wiring pattern should apply to the new unit. Make sure the hot black wire is connected to black, neutral to white, and don't forget to connect that green ground to the bare copper wire around the ground screw.