There are several 12V sources from several wiring harnesses can be found in the overhead console.
Outlined here is also the steps of pulling down the overhead console to expose the wiring harnesses.
There are four tabs holding the overhead console in place:
With a flat head screwdriver or a door panel tool, carefully pry out the front portion of the overhead console while pushing on the locking tabs.
pull down the overhead console front the front. The other side of the console (rear side) just sits on a rail on the lip of the roof liner panel. Do not pry out from this end!
Here's an image of where the side tabs mate with the roof liner panel
Here's an image of where the front locking tabs mate with the roof liner panel