Looks like a lot of us have gone thru a 'Seinfeld' episode.

A buddy of mine, an electrical engineer, had his tail-lights fail.
Used his wifes car until the electrical diagram arrived from the dealer.

Traced all the wiring in the car, tested everything engineer style.
It was the fuse.

PS - Radio still works, searchbar doesn't. Now I know what the wiires were for.