That looks like the wire that should be run into the second (rear)storage bay under the outside TV. That bay has a hookup for electronics to the outside TV. If you lay on your back, "slide" up under the side of the RV below the 2nd bay and look up to the top rear corner you can see where a cable like that goes. See Picture 1.
Picture 2 is all the wires that go into that spot (have to use your cell phone, extend your arm up and take blind pictures until you get a good one).
Sheree & Michael NCNG LTC(ret) with Munpi and Sheba (cat).
2016 Vegas 24.1 E350 5 speed "Ms. Enterprise", Bug-Guard Screen, Recliners, Infotainment Center, HUD, ARC Shower Rod, Safe-T-Plus, Curt SpareTire Mount,Tornado Black Tank Rinser, ext. WiFi Antenna, Roadmaster Tow Sys& Invisibrake.