Just for anyone who was curious about this puzzler: I have been living with the strange power step experience for the past several weeks by quickly pulling and replacing the fuse in slot 10 in order to extend or retract the step, but finally called Airstream tech support to brainstorm the problem. They got back to me very quickly with the diagnosis, though the repair is going to involve the hassle of a trip to the dealer. One of the two relays in the circuit for step operation is apparently stuck and only activates when power is cut then restored through the removal and replacement of the fuse. The responsible relay is either in the step well circuitry or in (behind, under) the kitchen cabinet.
2015 Interstate Grand Tour
WBCCI Member #5506