wiring help

Hi Long shot but does anyone have a picture or the wiring diagram of the downstairs cabin please? In the middle of installing the new headliner and the wall liner and found a long wire connected to the fuse coming through the back of the kitchen towards the seats and it has 12V in it. We don't...

I just picked up a 1973 Sea Ray 240 hard top from a family member who passed away, the boat needs some help and I was thinking about rewiring everything. is there a manual somewhere that would help me figure out what's what? The boat has a 302 with mercruiser outdrive, thanks in advance for any...