JD,
The automatic function comes from a float switch that is installed as an option. The float sits on the very bottom of the hull, below the inside floor The run function is activated to bypass the switch so that it will come on if water level floats the switch mechanism high enough to activate a switch to power the pump. When installed, they have an LED dash mount light that indicates the pump is powered from the float switch. Mine will come on even if all power is turned off. I have an optional battery isolator switch (PERKO) to kill all power. With that off, the pump will not come on regardless since it is mechanically disconnected at the battery with that switch.. The auto switch is good option to have...