complaint no high speed. display shows botton and wiring good.Swapped out steering motor , yes palletjack with power steering. swapped out complete head assy, steer gear handle ect. No codes. wiring and trouble shooting in book not good. Only show that this is caused by bad proximity sensor witch this jack does not have. Also steering gear reads zero at center. this one has me.... thinking main controller. any imput would be helpful.