What kind of light bulb (assuming that it's a light socket) fits in the little compartment in the trunk next to the battery?

 

Here's the picture.

[IMG]local://upfiles/8290/7100B72661224E23B4F89B0D7C0E6C2E.jpg[/IMG]

 

Sorry, wrong picture on the previous post.

[IMG]local://upfiles/8290/AAB4BCD1F9DD4B7EB91843AE01B8B0A8.jpg[/IMG]

 

It looks like a trickle charger socket.

 

Please elaborate, what's a trickle charger?

 

We used to install a slow charger on cars that would trickle charge the car while not in use. Some people didn't drive enough to keep the battery charged. Its a socket that went near the battery and you had a charger with a plug in that you would plug in to it. They were often wired through the fuse box.