Little 12 volt project

[Bluedog225]

I’m working on a little 12 volt project. A strobe through a 12 volt motion sensor and a battery.

I’m thinking I just wire the motion sensor in line on one leg to the strobe. Do I need to do anything with the ground?

Thanks

 

[Bluedog225]

Well darn it. Why does a little cigarette plug strobe have 3 wires?