Metalman
From page 4 of the electric step owner's manual
"If your step is equipped with a power switch, turn it off. The step should remain in the extended position with the understep light off when the door is closed. Turning off the power with the step retracted will hold the step in a retracted position as well."
It sounds like you may be bumping up against the "Last Out" feature of the step. The "Last Out" feature is also explained on page 4 of the manual. I believe the key is to not let the ignition switch automatically retract the steps thereby deactivating the "Last Out" feature.
If you have the Kwikee steps here is the manual for the older steps. The new model step manual is too large to attach.
In the FWIW category, an individual I rally with that flips motorhomes for his after retirement living told me that the motors for those steps are nothing more than a 12VDC automotive windshield wiper motor.