Originally Posted by wmeabates
Olds,A normal oil light swith closes when pressure drops.These fuel pump swithes open on a drop.Just a thought.Bill.
True. wire the relay so that the when the oil light switch closes it applies 12v,which will activate the relay. Wire the fuel pump ground through the normally closed set of contacts on the relay.That way when the relay activates it will open the normally closed contacts,therefore killing the path to ground.Using it this way the relay is "off" under normal conditions,rather than relying on something to be powered up continuously. Seems like less of a load,so more reliable to me. Thats what i had in mind at least.