I had a 05 Tahoe 36wtb 5th wheel.
The receptacle near the bathroom sink quit working one time. Found the breaker good but no power to the other end of the wire. I couldn't tell if the wire ran through the floor or the ceiling because because the wire went through a stud next to the J box.
I bought a cheap Harbor freight telephone tone generator and hooked it up to the wire at the receptacle end. I could follow the path of the wire and it went through the cieling. I removed one of the overhead lights and cut a hole in the ceiling just a tab smaller thian the light to access the wire. I was able to remove 1 staple and use the old wire to pull a new piece of romex. The black wire in the old romex melted in two after it shorted to the ground. It looked like when the pulled the wire they damaged the insulation.
This is the tool I used.