Okay, so the PO cut the wires and removed them when he pulled the stock tire carrier and the light assembly.
I installed known-good stuff from my dead jeep today. I replaced the bulb just in case. No-go.
I realized the PO had herculined over the contacts in the tub. I scraped them clean and lightly sanded the surfaces. They make firm contact with the contacts on the set I installed today, again, known to be good.
I did not damage or stretch or yank the wires or contact boots that I know of. But there is no dang light when we hit the brakes. Not even a brief flicker to indicate something being loose. It is dead.
How do I run the wires inside the tub from the contacts to where the line branches off from the main brake lights? Where would this be, anyway? I am pretty sure that the PO cut or damaged them at some time in the past. I hope they are merely cut and need splicing. I hope he did not remove them!
Any ideas, here?