I have a 2000S and it has an operating trunk light. I just went out and looked at it and took some pics for you.
There is a two wire lead that comes out from under the fire wall, and connects to the light. It doesn't hook up to the harness anywhere inside the trunk that I can see. It just disappears under the fire wall. My guess is that someone had the panel off at sometime and didn't hook it back up, and it is still under there somewhere hiding from you. Happy hunting.