cabin lighting

Hey everyone. I have a 2000 270 sea ray Sundancer with twin 4.3 Mercruisers. My issue is that all the cabin lights works intermittently. The ones I’m discussing are all 12V. No rhyme or reason that I can figure out. There seems to be a fuse block somewhere according to the blueprint drawings...

I am going to replace the indirect rope lighting on our 2005 420 DA. The rope ends on the starboard side of the bed and the other end goes into an area of the hull on the port side of the boat (switch is on the starboard side) that I can't see into or know how to get to. I cannot see it when I...