Check the reed sensor bottom inside of door on hinge side. It is a small magnetic two piece switch; if it has moved the step will not work properly. It is held in place with two sided tape. I reseated mine and solved the same problem. Also, suggest lots of lubrication on all step pivot points, a small bit of rust will stop the step. Hope this helps.
Put a small magnet on the sensor at the bottom of the door, and see if the steps work (with the steps switched on). That little sucker can get out alignment easily.