Ive noticed on earlier models the bilge switch has On/Off/Battery(auto) but my 2001 twin 717 only has On/Off. I had replaced the bilge pump and scrubbed the backet & bilge then noticed a sensor on its bracket and wanted to test the sensor by doing a controlled filling of the bilge with a hose & watching over everything carefully with the bilge off and the battery on and nothing! With or without key too. I think i tested the sensor plug also and it checked out. Let me know if you have some cool info/answers!