the wires you are looking for that are built into the wire harness, are on the harness near where it comes out from under the tank and heads toward the headlight, there you will find 2 leads, and on my bike the ones around the seat are located on the right side under the right side cover around the seat area. Be aware that these leads are not connected through the ignition so they are hot all the time. anything you plug in must be unplugged when you shut down otherwise you'll be jump starting the bike or charging the battery constantly.
I really have not found any good use for these leads ever. They don't work with heated clothing, they dont shut off with the ignition at power down, so they are live all the time. I am sure others have found good uses for them, I just have never met anyone who has.