Ok, that's connected to the controller. It will likely be in one of the storage compartments, screwed to the inside top, or directly to the bottom of the body, I would assume it would be near the center of the rig, but that could be wrong. Sorry I'm not much help.
2006 Damon Daybreak 3276 35'with 5 Star Tuner. 3 200 Amp Lithium batteries and 2000 watt PSW inverter/charger. 2013 Elantra on a Master Tow dolly.