You probably have a broken wire in the wiring harness.
Pull the switch from inside the coach.
On the back of the switch, there will be 3 wires.
The center wire is the common ground.
Of the other 2 wires, one is start, and the other is stop.
The start wire is the wire on the opposite side of the switch you press to start the genset. For example, if your switch is mounted vertically, and you press the top of the switch to start, the bottom wire will be the start wire.
If your switch is mounted horizontally, and you press the left side of the switch to start, the right wire is the start wire.
Determine which wire is the stop wire, and see what color it is.
Now go to the genset, and unplug the remote connector.
Use an ohmmeter or continuity tester to test the stop wire from end to end.
If it turns out to not be broken, let me know.