Big problem

Discussion in 'Tech/Mech General' started by nunny666, May 20, 2014.

  1. nunny666

    nunny666

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    Hi my vehicle is a fiat hyma b534 1994 , my problem is that when I had to pull fuse / relay box out from down by drivers side (holds the bullet fuses )I noticed thst the metal part of fuse box seems live , I get sparks when it touches chassis , exact same happens with 12 v isolator off , any suggestions or help appreciated
    The problem must be inside the fuse box ,on one of connections, or a live is touching the box somewhere ?? At a loss
     
  2. funflair

    funflair Funster Life Member

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    Hi

    Check it out with a multi meter as just one spark could be earthing some static electricity from you, if the meter shows it to be live then as you say there is a problem that needs tracing but can't help.

    Martin
     
  3. nunny666

    nunny666

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    Yep tested with multi meter if I touch metal box with one probe then you've chassis with other I get 12.8 v , thanks for time replying appreciated
     
  4. funflair

    funflair Funster Life Member

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    You say you get the same with 12v isolator off, the habitation 12v I guess. The fuse box you are working on will be from the vehicle 12v system so isolating the vehicle battery would/should stop it then you could check for a connection between the box and all the fuse holders on the box.

    Martin
     
  5. nunny666

    nunny666

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    Yes that's right buddy , tho their is a loop wth fuse and holder that links starter battery and leisure battery I believe
     
  6. hilldweller

    hilldweller Funster Life Member

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    There is a chance they are using the fusebox as an earth return for some wiring. Maybe you are turning something on/off, but what ?

    It can't be a dead short to 12V or you would definitely know about it.
     
  7. steevie

    steevie Funster

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    sounds to me like the fuse box back is just making up the earth circuit, and as said, it would be a dead short were it any other scenario. It needs to be clean and rust free when you bolt it back in place.
     
  8. nunny666

    nunny666

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    I have a question , if on multi meeting I get a reading of over 12 v on the fuse box , if I bolt that back in place will it not make the whole chassis live ? Or do I have my wires crossed pardon the pun , thanks again for advice , I was worried if a spark occurs it may start a fire , I shall disconnect battery while I fasten back in place to be safe then
     
  9. nunny666

    nunny666

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    Sorry my phones guessing wrong words again I mean if on multi meter , not meeting lol
     
  10. nunny666

    nunny666

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    Or is the 12 volt reading on the box because it isn't direct earthed to chassis and that's what you are all saying ?think I understand now
     
  11. nunny666

    nunny666

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    If I was to get some cable and attach one end to negative terminal on battery, then touch chassis with other end no spark , but if I did same with the fuse box, and touch it with other end if cable I would get sparks (with fuse box out ) so if I then clean chassis and bolt fuse box back , once in position it won't spark as it is grounded to chassis / correct ??
     
  12. Carol

    Carol Funster Life Member

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    Have you sorted it or has any one else got any ideas.
     
  13. nunny666

    nunny666

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    Just finishing work to go check it out bit I think if I clean the chassis points up , disconnect battery , fit the fuse box back to chassis , then re attach battery . It should be fine , think it's only sparking because it's away from vehicle chassis at mo , once bolted firmly in place it should be ok , I will try and then report back , thanks everybody
     
  14. nunny666

    nunny666

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    The only thing I am struggling with now is how it gets a good connection to chassis as the part of box screws go through is plastic ?
     
  15. nunny666

    nunny666

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    So interesting I connected a cable from box to chassis to see if it was ok while the box was out , it set on fire ???
     
  16. nunny666

    nunny666

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    So the box is either not designed to touch the chassis at all , ( if that's the case why not use plastic altogether and no metal , be a lot safer , or do I have a wire thsts wrong inside fuse box that's making the box live when it should be opposite , the box actually screws through plastic , so no metal will touch chassis , even the screws won't , maybe this is just how the box is ??
     
  17. nunny666

    nunny666

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    think I have found problem buddy I removed the block that connects all the wires in the fuse box , on one of the live wire bolts that the cables connect , it is stuck up and touching the metal housing , it has been replaced by someone at some point and dosnt fit in the recess like the rest , had tape on that rubbed through , thus making box live instead of neg , cheers for input let you know how it goes ,
     
  18. Hobbytwo

    Hobbytwo Read Only Funster

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    Sorry but you've lost me completely. The fuse box itself should not be live, only the electrics within it. Sounds as though the casing is shorting onto a live somewhere.
     
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  19. nunny666

    nunny666

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    That's exactly what it was , their are bolts which pass through plastic , the plastic is countersunk , so the bolt heads fit inside the plastic , in the past one of these bolts must if broke so got replaced , only trouble is the head of bolt fit flush not in countersink , so all they did was tape over head of bolt , the tapes rubbed off and thus making the box live , sorted now all I did was file head of bolt smaller to countersink it ,
     
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  20. Hobbytwo

    Hobbytwo Read Only Funster

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    Problem solved............well done.
     
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