I figured I'd write this up just for those DIY'ers out there. Sorry for the lack of pictures but this write up was a second thought. So, deal with it.
-Remove old plate mount and cut off vehicle harness side connector taking a few inches of the power and ground wire with it.
-Using a few feet of wire, tap into the Parking Light wire (white w/ purple tracer) on the passenger side rear. And tie a ground in.
-Run wires through tailgate to rear tire mount
-Splice wires with the factory connector that you cut off of vehicle harness
-Plug it all in, check operation
You will need to dismantle the factory plate housing so it will be unusable in it its factory location, so this is commitment.
I didn't get many pictures of this, but the molded plate housing can be disassembled into halves easily and the wires/connector/light can be removed. You will reuse the back side of the housing, the side the plate screws to because this holds the factory light. Some of the molding on the backside of the housing will need to be cut and removed to help it sit better inside your spare tire.
you can also get the Mopar plate hole cover from your dealer. Havent done that yet.
The length of wire I used to extend the wiring to reach the spare tire mount is tied in here. It was a length of ground & power leads in a single sheath that was extra from the Lux Lighting Rock Lights I just installed. So it worked perfectly. I used a T-tap connector to tap into the Parking Light wire as seen here. This is located on the rear passenger side tub corner, below the carpet.
Because the wire I used had both the positive and ground wires in one single sheath, I chose to run the ground in this location also. I scratched some paint off the tub and used a self taping screw to mount the ground wire.
Running the wire through the factory loom. I just cut a slit through the webbing and pulled it out. I guess you could take the time to take the panels all off so you don't need to cut the webbing to make it look better but that's your choice.
So once the wire is though the loom, these 2 black panels pop right off and the wire can be ran behind them, just like the factory wiring is ran.
You should probably run this wire differently and I didn't think about it until I had already tied the wires all together. But you can make the grommet hole bigger and run the wires though just as the factory wires are ran. I ran them beside the grommet as shown. It works. Doesn't look the best. But it's behind the tire so it's not obvious.
This picture shows the factory wiring connectors. Once you get your wire ran though everything you will then need to splice on your connector that you cut off the vehicle side harness from behind the plate. This connector will plug into the Plate Light wiring just as it did originally.
When dismantling the plate holder I cut off the cap that goes over the light housing. I just used a hack saw. it caps it off nicely just as your factory one does. Use some RTV to hold it in place.
Again, the finished product
The plate is now being held on by wire. I drilled 2 small holes in the plate and ran wire though it and tied them together behind the carrier mount. Not the ideal way to mount it but I was short on time and just needed to get the damn thing to stay. And it does.
All in all this took about an hour for me to complete. And that was on a whim, and planning things out as I went. Had I taken a bit more time from the get go I would have ran the wire through the tailgate grommet first. But I had already heat shrinked everything and I was running short on time. I still need to make something to hold the plate on more permanently. The plate screws fast to the backing plate just as it did. It uses the factory connectors so its super easy to remove if need be to access the spare.
Maybe i'll update this with better pictures when I get a chance. Including how to make the plate mount more permanent. This should get the point across though.
Hopefully you can learn something from this. Oh, and it's free!