On 4 cyl., pump initially runs in start position (ign. switch through fuse 23 through non-energized fuel pump relay). When alternator produces voltage at White wire with Green stripe, the "engine" relay is energized and passes current to fuse 12, through the diodes, and then energizes the fuel pump relay. Fuse 24 then provides voltage through energized relay to fuel pump. Keep in mind this means you have to have working alternator to have good fuel pump operation.