It would help if you could provide some additional information about your specific set-up and what you've done to troubleshoot the situation. What kind and model of power converter is installed in the PUP? Does it have any kind of rocker/toggle switch on it with labels such as "Shore" or "Batt"?
Is it all 12v devices that do not function or is it only the lights? Does the furnace, water pump, LP gas detector, refrigerator on DC setting, etc all work or are all of them dead?
How did you determine the galley kill switch is fine, by the way? If the galley kill switch is fine, such as there is 12v DC power coming to it, and from it when the switch/circuit is closed, then the break is in the wiring after that.
Answers to these questions will narrow down the problem area.
And FYI, wiring schematics are very hard to come by. However, I do have images of the 2001-2002 Fleetwood Bayside wiring diagrams along with some additional supporting information. Send me a private message with your email and I will send them to you.