Do you have a muiltimeter if so put it on ohms and check the neutral switch with the wires disconnected put the truck in and see if the switch is closed than see if when you put it in forward and reverse it is open if the switch is good than go to the keyswitch and find the start terminal run one wire from the start terminal of keyswitch to one side of neutral switch than take the other terminal and run another wire from other side of neutral switch to starter s post the small wire on starter that should make the truck start in neutral only.