The winch motor is connected directly to the battery and does not go through that fuse, so the battery needs to be there for the winch to work. If your battery was dead, and you lifted the roof on shore power, the converter in the camper was supplying that power to the battery through that fuse to work the winch.
My high wall, it is a 30 amp fuse, not sure if your model would use adifferent rated fuse or not.
HTT: "EscapeII" 2016 Shamrock 23WS (current)
PUP: "Escape" 2010 Rockwood HW 277 (gone)
TV: "Bruce" 2011 Dodge Durango V8 Hemi Crew
Just us gals (me, Sis and our daughters)
Traveled 19520 miles and 209 nights in 7 years and counting