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Urgent help needed please

Discussion in 'Technical Q&A' started by belfry, Jul 13, 2019 at 11:57 AM.

  1. belfry

    belfry Karting

    May 14, 2015
    129
    Image Unavailable, Please Login 1992 Mondial T rhd

    I have been trying to trace intermittent heater blower issues. I have found some dangerous shorting happening behind the passenger foot plate.

    I intend to fix (bridge) this damaged section, however, It would be very useful to know what this brown wire serves?

    Many thanks in advance
     
  2. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jan 11, 2001
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    Texas
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    Steve Magnusson
    It's not shorting. It's (I^2)*R heating in either in the swagging of those brown-black wires to their respective connectors or between the connectors. That brown-black wire probably serves the AC system (including the cabin blower), and the current is quite high (like ~15A steady state and even higher at blower start-up) so even a very small unwanted resistance like 50~100 milliOhms results many Watts of power being dissipated in a very small volume which heats things up a lot.
     
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  3. belfry

    belfry Karting

    May 14, 2015
    129
    Thank you. I’ve sorted out the wiring now and finally the air on, heater blower and fan speed issues are fixed!
     
  4. APA#1

    APA#1 Formula Junior
    Rossa Subscribed

    Nov 5, 2003
    818
    Central Florida
    Looks like some Testarossa wiring I have encountered :-0
     
  5. RedNeck

    RedNeck F1 Rookie
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    Jul 8, 2016
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    Matt
    Sorry but this is one of my pet peeves and shows that people really need to be better educated in basic electronics. A short is NOT a generic term for electrical issues, using this term can cause confusion when trying to explain a problem...a short circuit is 2 conductors that are unintentionally connecting and causing a signal to be passed along a different path.

    What YOU have looks like an overcurrent situation....and if you did not fix the actual component that is causing that condition, then you are going to have bigger problems, and you have not fixed the issue at all, all you did was splice a connection. My guess is that your blower motor is on it's way out, causing excess current to be pulled from you electrical system and if you keep using it as is, you could be causing more (expensive) problems. You need to figure out the root cause of your issue and actually fix it or you are asking for trouble.
     
    BOKE likes this.
  6. belfry

    belfry Karting

    May 14, 2015
    129
    Thanks for the advice. What would my next steps be? How would I go about checking?
     
  7. RedNeck

    RedNeck F1 Rookie
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    Jul 8, 2016
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    Try to find a wiring diagram online...you can trace the offending wire also, but that would be a difficult endeavor.
     
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