Wire Keeps Burning

Discussion in 'Chevy Truck Forum' started by Echo1, May 17, 2010.

  1. Echo1

    Echo1 Senior Member

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    the spot where the alternator and the starter wires connect keeps burning out between the firewall and the split. it happened once and i made a couple adjusments and put a new section in from the wires on another truck and it did it again in the same spot. its an 86 k10. i cant give much more info cause im not very good when it comes to wiring. anyone have any idea whats going wrong?

    [​IMG]
     
  2. Arkov

    Arkov Full Member

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    I had a similar problem with my Chevy S10. There are two possible options that I now of. You could replace the burning wire with a hire gauge wire, or you could replace the wiring harness with a new one. Although this option does cost a lot, in the end i do believe it will work.
     
  3. 75K30

    75K30 Senior Member

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    There is a bad connection somewhere, and something tells me that this silver painted firewall might have something to do with it. I could be wrong, but one might tend to think that you have a current problem associated with either a bad connection or poor splice or a bad ground.

    Can you tell us how you fixed the wire originally? and where the wires terminate (connect to)?
     
  4. Echo1

    Echo1 Senior Member

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    the thicker wire in that first picture i posted thats not burned goes to the starter here

    [​IMG]



    the one that is burned goes from the alternator here..

    [​IMG]

    to this split.. plus the piece in the firewall..

    [​IMG]

    to here..

    [​IMG]

    [​IMG]

    after the first time it happened i took the key out of the ignition which was on accessories. and the guy whos helpin me mightve done something else but im not sure. we cut the same section of wire out of the other set of wires from the other truck im using for parts and reconnected the negative on the battery to see what happened and it burned out again. we were not turning over the engine when it burned.
     
  5. Echo1

    Echo1 Senior Member

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    the split in the alternator wire has a fuse link too. right where it keeps going bad.
     
  6. crabtruck

    crabtruck Senior Member

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    Not good at wiring ? That's a pretty good write up of problem ! :applaud:

    First picture may be your problem, what is that circled, burnt gap ends?
    That plastic with the bolts for wire is your "battery junction block"
    and should be isolated fom the cab eletrically. Remove the wire from it
    and check that the bolts for wires are not short to frame/cab/ground.

    The part of the wiring burning out is likely a "fusible link" protecting things.
    If there is a short between battery and ground
    that passes through that it will blow.

    Your drawing is pretty good but missing a few wires.
    .
    [​IMG]
    .
    Suggest you disconnect battery ground and hot and wires at junction block.
    This will increase your safety while doing checks, looking for short or miswire.
    Unclear if this ever worked for you...

    Wiring pattern and location of connections varied but idea always the same.
    Electrically speaking, the hot on battery, the big bolt on starter,
    the big bolt on alt, the junction block, and the 1-3 bigger reds going
    into bulkhead are basically the same place. For their own build reasons,
    they moved the connection points around a little, sometimes using
    the bolt on starter as a second juntion block, besides one on firewall.
    There were fusible links in several of the wires acting just like fuses.
    Part of the design allows the alt to know if another wire has blown.
    Blowing a link by merely connecting the battery actually makes life easier.
    Eliminates most of the wires and devices as possible problems.

    With battery and junction disconnected, use an ohmmeter to check for shorts
    1) between positive battery wire and ground
    2) between junction-wire-to-starter and ground
    3) between junction-wire-to-alt and ground
    4) between junction-wire-to bulkhead and ground
    Verify using a good ground point by ohming between
    battery's ground wire and ground of your choice.

    If you find it in 1 or 2 verify correct connections at starter,
    else starter may be shorting internally.
    If you find it at 3 alt may be internally shorted.
    If you find it at 4 suspect list widens, wires join others for key etc.
    This is why you want to visually run down the other reds from starter
    and anything else hooked to battery pos terminal.

    Hope this makes sense and helps.
     

    Attached Files:

  7. Echo1

    Echo1 Senior Member

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    yea that first picture showed the part of the wire that burned between the link and the junction block.

    sounds like a good game plan. for the most part i get what im suppose to try, ill run it by my friend thats helping me. he'll know better than me. everything in this project is a first time thing for me. the more i work on it, the more i think dierks bentleys song "what was i thinking" needs to be playing in the back ground. lol
     
  8. crabtruck

    crabtruck Senior Member

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    Good plan... it's what the wire designers were listening to. :D
     
  9. Echo1

    Echo1 Senior Member

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    the problem was so stupid its comical...

    my dumb friend hooked up the battery terminals backwards.
     
  10. davbell22602

    davbell22602 Senior Member

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    My dumb friend that I have put a cam sprocket on backwards a year ago in my 90 chevy 350 c2500 when I was replacing the timing chain and gears.

    Glad you got it fixed.
     

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