What is this and where does it go. I think it is some kind of converter, and goes in the side box where the shore cord is stored. The previous owner Jury rigged the cord to work with out this box. He ...
The only component I can see is a large Relay. So Transfer switch is my guess.
NOW. if you have an older converter some of them have a 12 volt transfer in them but I do not think this is it. This looks like a 120 volt 30 amp transfer relay.