I have this truck and it is giving me fits. I suspected a bad lift amp and sent it out for repair to flight systems. Got it back and now have code 59, no current to steer motor. I changed the diode with no luck. The display blacked out on me when testing so I installed a yale display. I dont know if it makes a diff for electric steering and hyd. steering for the display but I dont think so. Can anyone help. Jim Fos