Clearly you must have "scared" them into working!!
So loose a couple of pounds and they will come out for you!!!
Ok, the step has 2 switches, a controller, a motor and the mech that you can see. Since they opened and you have cleaned the ground, I would suspect the Magnetic switch that is mounted on or around the door. On some coaches they are mounted on the screen door which is extremely flexible and the activating magnet will be just out of reach when closed. I'm sure that you have already messed with the controller plug to see if that will get it to function. Once in a great while the controller will go out, but it is seldom. Most steps us a magnetic reed switch that is designed for alarm systems. They just wear out, I've replaced the one on mine twice. Most of the time it is from getting tagged when loading and unloading the moho. One time it was the "what? not me's" (grandkids). This failure to operate happened the other day again to me and I wiggled the on/off switch and it started working again. The slide connector on the switch needs to be cleaned again. Steps are fickle things and nothing worse than stepping out in the morning with a full cup of Jo in your hand and wallah!!! no step....
So, if you see some fool laying face down just outside of his coach with a cup in his hand, it will probably be me!