Does all of your lights and everything else that uses 12V work? On our old 2006 'Cane, the main 12V breaker had a habit of popping for no obvious reason. We would still have 12V from the converter on shore power, but the minute we disconnected, all 12V circuits were dead. That breaker (very small push-button) was located dead center high in the engine compartment in the box where all the heavy duty 12V lines go in. You have to pop the cover off and then you can see the breaker.
If that's not it, you need to get a meter or 12V light tester and start checking for power. The first place I would check is at that fuse to make sure 12V is getting through. If it is, your ground is suspect. If it's not, start backtracking checking the 12V cable until you locate the problem.
