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Thread: Re: electrical short wiring damage

Discuss the Austin Healey Sprite and the MG Midget. Two different but similar cars sometimes referred to collectively as the Spridget.

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    Question Re: electrical short wiring damage

    Iím writing to ask if others have had a wiring accident similar to mine and to ask how was the wiring harness evaluated and fixed.

    My car is a 1960 Mk. I with an original, un-modified engine and wiring. My wiring accident occurred soon after a new Moss wiring harness was installed, while the car was being re-painted. Someone accidentally turned on the ignition switch (and apparently turned on the light switch, too), then walked away for several hours.

    The taillight fixtures and license light fixture were connected to the wiring harness when the accident happened, but they did not have bulbs in them. The lights in the front of the car were not connected to the wiring harness. (Most wires under the hood, and the panel lamps switch, were not connected, yet.)

    The lighting wire that goes from the ignition switch through the firewall was burned in two, close to the ignition switch. The wire from under the hood that returns through the firewall and goes to the rear lights was left mildly damaged, with some melting of the plastic covering (solid red in color) at the tail-light fixture. The melting was noticeable at the Right tail-light, but no melting at the Left tail-light.

    It looks like the damage to the red lighting wires was the only observable damage. Signs of other damage havenít been found, but the other parts of the harness have not been cut open.

    Have you had a similar wiring accident? What steps did you take to evaluate and recover from the accident?

    Thanks.

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    Re: electrical short wiring damage

    similar but slightly different. when I was restoring Ms Triss, I found a few wires behind the dash that had fused together. I carefully separated and replaced with shrink wrap and same sized wire - no problems since. It might also be a good time to add a relay or two - though a relay wouldn't have helped you here as I don't think anyone has ever put relays on tail lights.
    John-Peter Smit
    1976 MG Midget
    1969 Vauxhall Viva GT
    1958 Fiat Multipla (Barn art)

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    Re: electrical short wiring damage

    And as a tip, as I will be doing this in another week or two, do not connect directly to car battery until all circuits are tested and you know there aren't any short circuits. Install a plastic fuseholder for a 5-7 amp fuse between battery terminal and the new harness. Test each connection individually and validate current is there. Do them in order and make sure everything works correctly before powering up the car battery. It will save you from buying another harness and may even save your car.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Re: electrical short wiring damage

    Oh and make sure, are you converting from Positive to Negative Ground. Wiring for the most part remains the same but for someone who doesn't understand the difference that could be part of the problem. Rear wiring goes to the RR Tailight first and then jumps over to the LR Taillight. I'd think about replacing that entire piece that runs to the rear end. It's all bundled in the same wrap going to the rear.
    Jim Gruber - Apollo Beach, FL
    Bugsy I - '68 Sprite w BE Bonnet - Gone but not forgotten
    Bugsy IV - '60 Bugeye - 1,275+.040 and a 5-Speed - CA Car - 2nd Owner from new - 10/12 Painting done, reassembly, cutting, and buffing in progress.

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    Re: electrical short wiring damage

    Just turning the switch on would not have caused a problem if a dead short didn't exist some where. You will have to assess how much damage there is and how to repair it by cutting open the loom. My BE had had a dead short wired in when I bought it. To find out exactly where the problem was I used a in line fuze holder wrapped around one of the battery terminal bolts at one end and held to the battery post at the other end by a small hose clamp. It took several fuzes but I eventually found a dead short at the dash light switch. Had to replace some wire and the ignition/lighting switch. Lighting contact's inside had acted as a fuze.

    Kurt
    65,66 Midget
    57 Berkeley, MGA
    Working on quality rather than quantity

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    Re: electrical short wiring damage

    Thank you to JP Smit, Jim Gruber and Nomad for answering my call for help. I am un-educated about car wiring, but I want to work my way through this problem and learn something.

    So far, it looks like the Red lighting wire that branches off to the back of the Bugeye was the wire that shorted (shorted at the Right Rear taillight), when the ignition switch was accidentally left on.
    (All of the rear wires were connected to all of the rear light fixtures, with no bulbs in the fixtures.)
    The Red lighting wires that branch off to the front of the car look undamaged. The front Red wires were all disconnected and apparently not shorting on the engine, frame or body.

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