It could be a bad circuit on the converter, I've had the same issue. If you know which fuse protects the lights that are out, disconnect the wire from the fuse terminal and touch it to a known good circuit, make sure you turn one of the lights on so you can see it. If the lights work then switch that wire and fuse to an empty slot (if there is one).
Hope this helps, I spent 2 seasons trying to figure out why our main slide had no lights.
🇨🇦 Scott & Janie 🇨🇦
2004 Dodge RAM 2500 CTD (slightly tweaked)
2011 Cruiser 31RK
Cooper the Golden Retriever, and
Sam the black lab.