I'm changing my trunk light as well and my bulb is burnt out and I do have power to the socket. What I would like to check is if the switch is turning off the light when the trunk is closed. I don't think I can fit in the trunk. Some times the Germans over engineer things. I know you've heard that before, I didn't just make that up. I looked up the bulb on Osram Sylvania and the bulb number is 6418. The one I took out is a Phillips K25673. I know before I bought the car that it either had a dead battery or the battery was disconnected, so I would like to be able to check to see that the light is going off and not constantly draining the battery when not in use.