Originally Posted by jconly
Ah that totally explains it.
Looking at the wiring diagram, every drawing of the pump showed that fuel level sensor and I was a little confused, assuming that's what the third wire was for. Oh the redundancy.
I wonder if they activate at different levels?
regarding levels, yes they do activate at different levels due to the different mounting location (between Adv and SD tanks). However, due to the volume and shape of tanks, there will be close to same amount of fuel left in both tanks (approx 4 litres ?) when the sensor activates.