I had a strange thing happen the other day. My starter ran away on me. it stayed engaged while the engine was running but not engaged to flywheel. It continued to run full out after the key was removed and I had to disconect the battery. There was smoke coming from under the truck. I replaced the starter and it worked fine for about 10 starts. I have checked many things out and traced to to the orange and black wires going to the neutral safety switch. I have 12vdc on the orange and black wires until the switch is set to P or N position. The switch shows conductivity where it is supposed to. that means I do not get 12vdc to the black and white wire. Since i see voltage until the switch is closed it makes me think there is a short somewhere. I need a diagram to chase it down.