Ignition coil polarity

Electrical & Ignition

  1. Jon O.

    Jon O. Well-Known Member

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    1972 Chrysler Newport.
    I made the dumb-head mistake of taking out the ignition coil without looking at witch wire went where. Based on the curvature of the wires, it looks like the + side went to the distributor, and the - side to the firewall. Is this correct?
     
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  2. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    Running points?? Black wire from Distributor goes to negative,blue wire to positve if my memory serves me right
    Besides, if running the original coil,the terminals can only go on one way.
     
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  3. Jon O.

    Jon O. Well-Known Member

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    Yes with points. Both wires are black. One comes from the direction of the firewall, and one comes from the points. On this coil the wires can be put on either side? I don't get what you mean by they can only go one way. One side of the coil is marked with + and one side with -
     
  4. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    That is IF the car still had it ORIGINAL coil.
    Prolly been replaced at some time.
    The coil should have + and - marked on it.
    Feed wire from engine harness goes to positive,distributor wire goes to negative.

    Get a shop manual that has wiring diagrams,they are a big help for future snafu's.
     
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  5. MrMoparCHP

    MrMoparCHP Senior Member

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    The only one way is referring to the terminals, I believe one of them is D shaped and will only go on the correct post.
    An original harness should have a blue wire coming from the harness, either it has been replaced or it is dirty.


    Alan
     
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  6. 413

    413 Active Member

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    They are both D shaped from factory. They can go on either side when D shaped. When coil gets changed so goes the D shaped terminals.

    On the original question THINK this over. Does it make sense that the wire with power should go to the + terminal?

    The points are a switch to ground to tell the coil to fire the spark. The distributor needs to be grounded or no spark. Remove it from the engine and spin it in your hand = no spark.

    But it’s good to ask and be sure to avoid the smoke test of electrical parts.
     
    Last edited: Jan 13, 2020
  7. Wildaugust

    Wildaugust Senior Member

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    If you're running points, then the negative terminal of the coil connects to the distributor. With Chrysler electronic ignition the distributor wouldn't be connected directly to the coil.
     
  8. Jon O.

    Jon O. Well-Known Member

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    Thanks to y'all for the help. I went back and did a close inspection of the wires. Yes the one is blue and just dirty. Based on the out of roundness of the holes, I believe someone drilled them out to make them round holes. (If it works, fine by me.) I got it hooked up correctly. She's runnin good as new.
     
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  9. rkrochen

    rkrochen Well-Known Member

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    It is possible to connect the coil backwards if the terminals and or coil have been replaced. If this happens the car will still run but lack power and performance. If you put it on an oscilloscope the pattern would be upside down.
    I had a customer come in one time with a six cylinder, I think it was a Hudson and it had no power. He had it to several shops and no one could diagnose it. As soon as I hooked it up to the scope I could see the problem.
     
  10. bluefury361

    bluefury361 Old Man with a Hat

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    [QUOTE="Jon O., it looks like the + side went to the distributor, and the - side to the firewall. Is this correct?[/QUOTE]





    NO...... + to the feed and - to the dist.
     
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  11. 70bigblockdodge

    70bigblockdodge Old Man with a Hat FCBO Gold Member

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    Plus to ballast resistor, negative to points.