Mystery Switch (pics)

Hi folks!

New member and owner of a 2003 Dodge Ram Cummins. I apologize for making my first post a question, but this one has me completely stumped. The truck had a few aftermarket switches in it. One I figured out goes to an EDGE tuner (solved that one fairly easily). The other one is completely unrelated, and that's what I need your help with.

The switch is a two way rocker (can be moved down and up, but is spring loaded back to the middle position). It has two wires coming out of it. One wire from the switch goes straight into a spare fuse slot in the fuse box (assuming power supply). The other wire from the switch loops all the way around the engine to the passenger side and splits into two wires. Each of the red wires go into a terminal of some sort underneath the passenger side battery (see pictures). Despite my best efforts, I wasn't able to figure out what it controls.

The truck was set up to be towed behind an RV in its past life, i'm not sure if that has anything to do with it.

Thank you in advance for any insight you can offer.

Scott

Some one will be on here soon that can shed light on that switch circuit.

One thing that springs to mind with a switch like that would be a winch, if the truck has a front receiver chances are he had a removable winch.

Winch makes sense. The pass side battery is the auxillary crap isnt it?

Are those terminals connected to anything else.