I had the "stuck extended" problem not long ago.
I got under the step, disconnected the 2-wire connector at the motor, hooked jumper leads to the coach batteries, and tried actuating the motor. Nothing, just clicked. reversed the leads, and the steps started to retract. So, ensuring that hands and arms were out of the way, I retracted the steps fully, then extended them a couple of times.
I re-connected the motor connector, and the steps have been working fine ever since.
I have no idea what went wrong, nor do I have any idea what I did that solved the problem, but the steps are working now
I guess that is all that matters...