[Greg Reid]

It works fine now with the one wire attached and the ground plane connected to ground with a jumper. Switch opens the connector to the ground plane so it goes off.... As for the second wire, well it's a mystery to me. That drawing clearly shows wires on both prongs...Yet the schematic just shows a ground connection and a power connection.
I may ask someone who has an original untouched one to take a look. The car I pulled this one out of was very original, but the dashpad had been removed and was lying in the floor. I took the light out when I noticed it was still in place.

Like I said, I don't recall that light coming on in my other car unless I switched it on. It was an untouched original car. Just doesn't seem like a map light should come on with the doors open....but I've forgotten more important things than that in the last 25 years...lol

By the way... I believe the light will get a good ground just with the screw in the dash. I checked that metal hardpoint where courtesy light mounts into and it's got good continuity with the exposed metal parts of the dash over the instrument panel.