Does the pump run prior to the fuse popping?
I just swapped out a Rule
that had a plastic wire tie wedged into the impeller, locking up the motor
, which killed it. Dead short once locked up...
Also, did you wire the float switch directly off the battery
? I've seen that done before. Possible that wires are spliced in to the pump opposite polarity? That would be a dead short to the battery, with an open circuit with the panel switch off. Does the pump ground out to the panel, or does it use a common ground somewhere else? A chafed through positive wire on a common ground would do it if the water
level is above a bonded component like a through hull
Do you have a pump that only has 6 inches of wire coming off of it? Shrinking butt connectors and shrink tubing on top are about the only way to go... If a regular nylon butt connector is underwater somewhere that will do it too.
Good luck with it! I always have the best success with this stuff by disassembling the system and testing everything individually. Start with the biggest problem you can think of and work backward to more complex things.