Identifying broken wires?

I'm writing an article about broken wires in cars, does anyone has experience in the field (electrical engineering, auto technician) and can tell me various ways of fault diagnostics, how to find a broken wire and what could be the cause? thanks!

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  • 7 years ago
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    In any environment where the platform is mobile there are several primary suspects when trouble with electrics arise.

    First most would be vibration over time will shake a connector or connection loose.

    Second most will be environmental factors; fluids or rusting.

    Third is a wire which has been pinched, cut by later installs, or simply strapped to tight to begin with.

    Since you want automotive specific; I have to add wires run into doors and hatches, no wire stands up to serious flexing .

    Ok that covers the causes. Yes when something quits working altogether, wires have to be considered. Before that often a connection gets loose, or bolt becomes rusted which results in something working intermittent or erratically. There again wires before full fail may have strands break due to vibration and flexing. Resulting in lower voltage and current on that wire.

    There is a further special consideration for vehicles. That of a DC power cables. Often the wires are run from weak secondary points, instead of run to special power taps or all the way to the battery. Sometimes this makes a frequent blowing fuse, sometimes just sluggish operating devices. The most repeated problem with power wire, is to have the common (ground) depend on the vehicle body or frame; rust becomes a big factor. Worse the device will start using its mount (often loose) as a ground connection; something will in time fail then.

    Diagnostic is all about isolating the various factors; and when you think you've found it run a temporary jumper in it's place to test the fix. With all systems the first thing you check is the power source, in your case the vehicle battery; and you must observe it under all conditions. Car off, car running idle, when charging system is and is not boosting the voltage, with and without heavy load (lights horns and more) on.

    Hope all that gives you some insight: good luck.

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  • Anonymous
    7 years ago

    Broken wires are going to lead to an open circuit, or something not being powered like it ought to be.

    In a car, the distances are limited to a few feet and the obvious method is to follow the +ve 12volts from the key or the battery to the thing which is not working. Be clear about what it is which is not working; think about does it normally only work with the Ignition key On or can it work while keys are not even in the ignition ? Is there a fuse box ? Do you have a handbook to tell you which if the fuses it is and what value to replace it with, if indeed it is the fuse ? If it is the fuse, do you know what might have caused it to blow ?

    A lot of diagnosis is done from simple operations and observations. Depends again on what is 'dead' and what is near that in the way the car works and is that still working ?

    A lot of focus is on the live being faulty but what about the 0v return ? No longer do we use the body of the vehicle as the return (causes corrosion). We use a black return circuit wire to every item but when this path is broken or disconnected, the problems are just as bad and may be more difficult to find. Electricity will always look for a return path and you may just see that in something else nearby, telling you it's a bad local return connection.

    If you want to be a full time auto-electrician, a test lamp for 12v would be very useful. This might plug in the cigarette lighter for a 0v condition, through the bulb, looking for the +12v supply. Otherwise a voltmeter is fine. Remember that the car battery has a huge amount of power in it and trailing leads around from the +ve is not to be done without thinking.

    Another industry where broken wires are bad news is the telephone Linesman's area and I know that experienced faultsmen can tell from the capacitance remaining where the point of the break might be. A lot of this is now automated but consider the telephone wire, spreading out under the town as two parallel conductors forming a capacitor. They prefer an analogue meter to read the kick of the capacitance remaining in the pair of wires and this gives them a clue as to how far away to make the next check

    Source(s): Life in telecommunications and working with car and boat electrics too.
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  • 3 years ago

    in case you are able to hold the twine, flow alongside it along with your palms. the place it bends unexpectedly is the place it particularly is cut back or broken. in case you have the twine separated, then run a low voltage on one section and employing an LED or indicator and a pin related to it, poke the pin at different factors until no sound is heard, the place in all probability the subject exists.

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  • 7 years ago

    If your radio or lights stop working.

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  • 7 years ago

    Yes. I could. Learn to spell. (And go fish)

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