Hot wire the motor/gear assy w/ a positive and neg directly from a battery.
If the motor/gear runs, the step will go up and down by just reversing polarity. This bypasses the controller, and all the other electrical involved in the auto step operation. If you don't want to deal w/ the expense of replacing the controller, or anything else the fix may involve, just run the pos and neg thru a momentary 2 pole, double throw (6 terminal) switch on the wall to reverse the polarity, which will then be a manually operated electric step.
And yes, keep hands and body clear of the steps when working on them !!!!
Rich
'01 31' Rexall Vision, Generac 5.5k, 1000 watt Honda, PD 9245 conv, 300 watts Solar, 150 watt inv, 2 Cos 6v batts, ammeters, led voltmeters all over the place, KD/sat, 2 Oly Cat heaters w/ ox, and towing a 2012 Liberty, Lowe bass boat, or a Kawi Mule.