1987 260E

Appreciate suggestions for tracing repair:

Ran an air compressor off of the cigarete lighter. It overheated. The lighter and radio are out, and the fuse is blown.

Changing fuse... It immediately blows.

Where should I look for a burned wire? How do i get access behind the ash tray? I pulled off the wood panel around the tray to discover that it was stapled on from behind and wasn't supposed to be removed this way.

Thanks, in advance!