My '63 Thunderbird trys to start itself in Park and Drive. What does this mean?

How do I get to it? How would I replace it and/or how much does it cost?

The neutral safety switch is mounted about halfway down on the steering column. You'll have to crawl under the dash and look for it. It will have two wires going to it, Should probably a black and a light green wire though the colors might be different on the T-Bird. Anyway, it will have a plug at the end of the wires attached to the switch which is a silver metal color and black plastic. The neutral switch basically is a cutoff switch that only lets you start the car while it is in Park or Neutral, thus the name. It could be grounding out thus letting the car start but then it would start in any gear not just park and drive. I believeit could be the starter solenoid under the hood on the passenger side fender apron. It is where the battery cable connects to. It should have one or two small wires on top and two heavy studs sticking out of the sides with battery cables attached. One cable goes to the battery and the other goes down to the starter. I believe the Ford/Motorcraft number is #SW-3. They should have one or equivilent at most auto parts stores. Unfortunately they won't be able to look it up at the parts store as their computers probably won't go back that far. PepBoys goes back to 1968. Advance Auto goes back to the early 80's. Forget AutoZone as they only go back to 1992. If you have an O'Reily's Auto Parts near you, they should have that Motorcraft part in stock, bring in your old one to match it up in the store. Any good Ford dealer that's been around a long time should still have the old parts books under the counter where they could look it up but It should be an Autolite/Motorcraft SW-3 which they just might have one in stock too though O'Reily's will be much cheaper. the electrical problem you have sounds similar to one I've had a couple of times in the past. Both times it turned out to be a starter solenoid that was stuck closed. The contacts sometimes "weld" themselves together and cause the starter problem you've described. If it has Autolite printed on it then you'll know it's original to the car as Ford sold Autolite to the Bendix company in 1970. Any electrical switches on a Ford after 1970 were made by Motorcraft which Ford still owns. So without actually seeing the car in person, I would say it's the starter solenoid that's probably gone bad. Also while you're at it, check the wires going to that switch for cracking and/or breaks in the plastic coating but be careful as old wires get very brittle and can snap easily if not handled carefully. If you see any breaks, splice them back together and tape up the connections with black electrical tape. The parts stores sell plastic convuluted tubing in black and a variety of other colors that can be put over the wires to help prevent them from melting from the engine heat. A little Die-electric compound or Vaseline on the solenoid connections will keep them looking good too. Vaseline works great on the battery terminals also. Keep us posted and Good Luck, Kenny/MrBlueOval. .