isnt the bilge pump bypassed the off battery switch? I know that trash can cause bilge pump to run all the time. This happend to my brothers boat and it drained the batteries while we where having a lunch.
I got a balloon stuck in my Bilge pump and it wouldn't turn off by itself, it's easy to clean it, the bilge pump can be removed and cleaned by sliding the latch and pulling the motor out, it only takes a minute.