Check the fuse
On my Hunter 31, there is a hard wired circuit, direct to the batteries, for the auto bilge pump. It has a screw-in spot on the breaker panel with a fuse in it. If you manually lift the float switch and the pump does not turn on, check that fuse first. My battery switch does not have to be turned on for the auto bilge pump to work. Yours shouldn't either. This defeats the purpose of the automatic feature. You should not have to leave your battery switch turned on to achieve the safety of the auto bilge pump.