I believe it is possible on a 3G to make it "self exciting" , in other words, work without plugging it in to the vehicle harness. I can't remember exactly how but I think that you have to plug in the stator wire to one of the three prongs on the three prong plug spot and maybe run a wire from the back output lug to one of the three prongs also. Someone else might be able to make a diagram or try searching the forums more for someone running a 3G without the factory harness.