On our rig, the steps will move in and out when the door is closed if the step switch is in the on position.
If the engine keys are in the ignition it will also, usually, move in and out even if the step switch is off.
Initially, after shutting off the engine and removing the keys from ignition, the door must be closed two times to then get the steps to stay extended by then turning off the step switch.
I do not know if this is standard behavior, but you might test yours against the above parameters.
1995 CC Magna #5280
C8.3L 300hp Cummins, 31,000lbs