Re: electrical fault
Don't know your particular boat but it sounds like a disconnected wire or a fuse. If you don't have a Digital Multimeter get one. Harbor freight actually has some decent ones. I carry one in the boat and the RV.
Most DC circuits are pretty simple. 12v from battery to switch (fuse in between) with switch on 12v to gizmo (light, pump, horn) ground wire from gizmo back to battery. anything not connected gizmo stops working.
With 3 items all not working I'd look for a wire not connected near the battery first