1) light switch could be on dash
2) What was the shore power 20 amp 30 amp or 50 amp?
If shore power inadequate the electrical management system might have locked out operation to prevent overload. Specially if the a/c was running and you were on a 20 or 30 amp circuit.
The owners manual states;
For operation of the slide-out room the following is required:
Park the RV and level it for stationary use
Ignition on (engine running)
Transmission in park
Parking brake engaged
Slide-out key or switch activated
was this the case?
Traveling with my best friend my wife!