Originally Posted by pedZ

If you use the pre-wired harness, the best option is to tap into the BCM wiring like in this thread.

DIY: Rear Fog Light Wire Via BCM and Stock Wiring

You'll just have to run the wires from the BCM to the center console and connect them to whatever switch you use. Oh, and you'll have to add a diode like Spearfish talks about in the DIY. If you are using a switch without a LED you'll have to run two wires, and with a LED will need four wires.