While I certainly realize the desire for a “quick and easy” swap out I don’t think that this is one of them. As others have mentioned the main issue is the BCU, the switch doesn’t really control the lights, it controls the BCU which then illuminate the rear fogs if certain other conditions are met (marker lights on). I don’t think the BCU can be reprogrammed to ignore the condition of the marker lights being on. How electrically inclined are you, would purchasing an off the shelf relay and wiring that up with it’s own button/switch be OK? I don’t think you are going to be able to get out of running a length of wire back there at any rate, there’s no constantly “on” 12V source back there- even the accessory plug requires the vehicle to be on.

 

I found a "quick and easy" solution. I updated my original post with the details.

I am mechanically & electrically inclined. I've wired up other aux lights on the truck, and even have a really nice pre-built harness with a switch and relay. However, I'm also lazy and really didn't want to add a new run.