My new to me 2015 FR3 purchased by my wife and I less than a month ago, it had 24K miles.
Last weekend while working on the cab A/C, the steps stopped working. No noises, they just stopped. I took off the motor assembly, to find that the commutator was blackened, and the main gear (nylon) was damaged, presumably by the motor attempting to drive the steps down when the path was obstructed by a curb or something. I cleaned up the commutator with sandpaper, and filed the teeth.
I read the threads about putting a switch in place to stop the motor from running, so the steps would not be stopped by an obstacle and become jammed and damage the motor. I was concerned though, because knowing myself; I would drive off, sooner or later, with the steps deployed and locked down, and damage them big time.
So I came up with an idea. I would use a normally closed relay to control the power to the steps. The relay control coil would get its ground only when the emergency brake is on AND a switch added to the battery disconnect panel is closed. If I inadvertently leave the step relay switch closed, and try to drive away, releasing the emergency brake will remove the ground from the relay winding, and the relay reverts to its normally closed condition and the steps retract.
I found the best and closest place for emergency brake-controlled ground at the Lippert Leveling Control connector. The power input plug only has two wires, red power and white ground (only grounded when the emergency brake is on. I tapped into the white wire, soldering a wire running across the underside of the motor home to the Coach Battery Compartment, and up into the battery disconnect switch at the top of the interior stairwell.
I inserted the n.c. relay at the green fused wire providing power to the step system.
I can lock the steps in the up or down position, but they will retract as normal when the emergency brake is released.
I am enclosing some pictures and a rough wiring diagram.