There seems to be some question regarding the wiring of motorized steps, the OP's rig shows that it has Kwikee steps and I have included a copy of the Kwikee schematics from manual #888. I have also included a copy of page three of that manual regarding, the Auto Extend feature and how I stow my steps for storage.

The schematic outlined in red is the one for use with a magnetic door switch.

I hope this helps with the wiring and how to include it in the battery disconnect. The chassis battery is the one shown.
This is how I stow my steps.