Sure, start at the helm switch. An automatice bilge pump usually uses 3 colors of wire, black, brown, and red.
The BLACK wire is the ground - leave it alone for now.
The BROWN wire, even though it might route to the auto bilge switch (unless auto pump) then it goes through/to the pump too) is 'typically' wired to be used for MANUAL operation.
The RED wire is usually wired for AUTOMATIC operation.
I'd pull off the red wire first and see what happens, from the dash connection. It the boat was ABYC wired correctly, and the pump stops - then you have just disabled the AUTO side of the circuit that was faulting. Now try the MANUAL switch to see if the pump still operates.
If so, sounds to me like the float switch went bad. Note: some are mercury filled switches - so be careful AND environmentally concious (sp?) and dispose by bringing to local FD. Noted marine surveyors like Dunk recommend the Sure Bail brand if using a traditional float switches, though there are full electrical capacitance ones on the market now, i.e., no moving parts, wet finger tips and touch contacts to test ...
Hope this helps!
