[ReelMagic]

There is another switch as you mentioned on the wiring diagram....It;s located on the through-the-hull valve for the overboard pump-out....The purpose is to ensure you have the valve open when you turn on the macerator/overboard pump......At least that's the way my 38 open is wired.... BTW I had that switch fail which prevented the pump-out from working.. replaced the switch and all working AOK