Often electric steps have a switch near the entrance. Set one way, the steps retract when ignition is turned off or when door is opened. Set the other way, the steps retract and don't open with door or ignition. Check for any switches near entrance. Also you could search for manufacturer and model of the steps and search for a manual online.
On many models, the batteries are under the steps, see if any of them lift up.
Luckily, Winnebago does a great job on having all manuals, plumbing, and wiring diagrams available online.
Winnebago Industries Operator Manuals
Since the RV is 26 years old, to get a real idea of what's original and what's been modified or updated, I suggest you poke and peer in every cabinet, closet, and compartment and list make and model of everything you find labeled. Also note any fuses or breakers. Then use Google to download manuals for all found items. You'll spend some time, but you'll know your RV much more than you did.