I got back to the project and found not one but two crossed wires. One was clearly a bone head mistake but the other was a bit more subtle. I had the Van painted many years ago and some paint over spray obscured the the wire color codes on the right front light. If I was paying more attention, I would have pealed back the harness tape to confirm the correct wire colors. But noooooo, that's too easy.

Anyhow, the lesson learned is to replace all sockets, clean ground connections and wire correctly to renew the lighting system.