switched power wire

I need the switched source under the door trim panel to connect a small LED strip. I read on facebook a guy used the window power switch. I have no idea what cable should I use.

Hi all, new to the forum, happy first time mustang owner (2015 gt premium) by way of challenger r/t then bmw 2 series, not new to the modding-scene(not a pro either) but hoping someone with knowledge can help me out. All I need is the color combo of the wire that indicates the 'switched power...