On my 4dr, I tore apart the tail lights. I needed to wire up running lights + 3rd brake lights to the spare. I have a cheapo license plate running light with integrated 3rd brake light. In case anyone cares what I did:
- The tailgate has a harness for the brake light and ground
- I ran a wire (yellow) from the same area in the tailgate, through the wire sleeve, into plastic conduit and routed it down across the floor sub pan, up to the other corner of the tub. I then spliced it into the running light wire on the old license plate frame harness.
- I label wires so subsequent owners know where they go.
Also while I was in there, I was reminded that I just left the resistance capacitors dangling. They melted a bunch of stuff, so I needed to fix that. Lesson learned.
Now I just need to mount them against the internal sheet so they don't cause any more trouble. My plan is to drill two small holes in the internal sheet and use a steel zip tie to hold them against the sheet. Should have done that originally.