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Automatic transmission safety switch

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  • Electrical: Automatic transmission safety switch

    This one is a puzzler for me but I know there is someone on this forum with the answer. My 57 silver hawk does not have a safety switch. I found out the hard way. I have purchased a used switch and I need to install it. I have attached photos of the switch.

    I have also found the wiring diagram showing where the four wires from the switch go:

    1. Black-oak to the light switch.

    2. white-red to the ignition switch.

    3. white-black to the back up light switch ? Where is this?

    4. white-red to the starter solenoid

    Where I get lost is knowing which post on the switch connects to which colored wire and there are multiple connection points on the unit being connected to on the terminating end of each wire. Which point does the wire connect to?

    If anyone can look at their connections and tell me where each end of any one of these wires goes
    it would be greatly appreciated. That would cut down the odds of my screwing up again. Thanks
    Attached Files

  • #2
    That is a combination starter safety and back-up light switch. One pair of terminals is for the starter, the other for the back-up lights.
    Do you have access to a multimeter or test light? If so, find the pair of terminals that have continuity when the switch is in the park position, they would be for the starter wires(white-red). Move the switch to the reverse position and the other contacts should show continuity. These would be for the back up lights(black-oak,white-black), if you have them, unused if you don't.
    Last edited by 1954khardtop; 05-16-2011, 05:19 PM. Reason: add wire colors
    Dwight 54 Commander hardtop


    • #3

      Thanks for the great information. I checked the switch with a multimeter and it looks like the two round connection points (1 male, 1 female) have continuity in the park/neutral position.
      The two flat connection points have continuity in the reverse position. I have backup lights but not worried about them working at this time.

      The next step is how to run wires as there are no existing wires. Am I correct in thinking I need to find the wire that runs from the ignition to the starter solenoid and attach it to one of the points on the switch and then a wire from the other position on the switch to the starter solenoid? If that is correct, what is the best way to identify the wire as the colors on the wiring diagram are not the same as what is in the car? Would it be identified on the back of the switch? Thanks again, I really appreciate your input.
      Last edited by aftontrix; 05-17-2011, 08:16 AM.


      • #4
        All you have to do is break the wire going from the starter terminal of your ign. switch to the solenoid thru those contacts. You can reroute your exsisting wire if it will reach, or replace it. Matching the color code is nice, but not absolutely necessary. When I make additions or modifications using non stock colors, I draw a picture and write down the colors I use. I keep it in my shop manual with the wire diagrams. Hope this helps.
        Just read your post again and see I missed the point. The starter terminal on the ign. switch should be marked with an S. If not you can find it with your meter. Get a helper to turn the key for you while you check the terminals for voltage. The one you want will only have power when the key is in the start position, it will go dead when the key goes back to the "run" position.
        Last edited by 1954khardtop; 05-17-2011, 01:59 PM.
        Dwight 54 Commander hardtop


        • #5

          Thanks again for the info. It is now installed and working.
          I looked at the back of the switch and every wire was black so no help there. I then looked at the starter solenoid and there were only two wires attached to separate posts, both white. Fortunately, the two posts had a stamp under them on the solenoid body one was an S and the other was an I. Obviously that was for starter and ignition so I spliced into the S wire.
          Last edited by aftontrix; 05-18-2011, 01:10 PM.


          • #6
            I'm doing the same thing with mine. It was originally an automatic, had been changed to manual. I'm putting an auto back in.
            Dwight 54 Commander hardtop