Here is the kit:
Once you pop off the red plastic lens, you can see that its just an incandescent light bulb and two power leads.
The stock jeep wire harness used to plug into this spot on the back of the 3rd brake light. You can see that there were two pins.
I just cut a Size 8 stud crimp connector in half to make a "pin" for the end of each wire.
The I plugged these into the stock wiring harness and tapped it all in place securely. Then I traced the holes in the plastic backing of the light onto the spare tire mounting plate. Unfortunately they didn't quite line up with the pre-existing holes in my Expedition One carrier. I drilled out the holes.
Here you can see the stock wire and wiring harness with the Hard Rock brake light attached.
Screw the white plastic backing onto the tire carrier, and then snap the red lens back on.
That's it, you are done! Ok, maybe not. The light didn't work.
Turns out I blew a fuse. That's because the white wire has a stud crimp connector on it (the hoop) which the screw goes through. The screw is bolted into raw metal in the tire carrier which is connected to the frame, adn therefore grounded. So every time I hit the brakes, a ground fault ocurred and blew the fuse. I had to go back into the light and use a dremel to cut out part of the copper away from the mounting hole. Then I re-drilled a new hole to attach the white wire to the copper, leaving the mounting screw electrically disconnected from the white wire/copper. No more ground fault and the light works great.