Another electrical issue, 30a Megafuse blows, no trans lockup!

Discussion in 'Audio & Electronics' started by Richardsia, May 3, 2019.

  1. Richardsia

    Richardsia Junior Member

    Age:
    64
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    Joined:
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    Location:
    Nevada
    Ram Year:
    1994 - 2010
    Engine:
    5.9 and others.
    Now working on several Dodge diesels.
    Problem of the moment is that the '94 2500 does not charge properly despite a new alternator and the trans does not lock-up properly.
    I've found that the relay controlling the alternator regulator switching has no power.
    It has no power as the 30a "Megafuse" blows immediately on installation.
    Without proper voltage the trans does not work as it should either.
    Engine starts and runs fine.

    What I would really like to find is a schematic of only the circuits that depend on the (#4) 30a megafuse to ease tracking down the short.
     
  2. Richardsia

    Richardsia Junior Member

    Age:
    64
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    3
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    Joined:
    May 3, 2019
    Location:
    Nevada
    Ram Year:
    1994 - 2010
    Engine:
    5.9 and others.
    Well it looks like I am getting close.
    Got a magnifying glass to read the Chilton schematic.
    Seems it's probably the wire to the alternator and PCM.
    Hoping it is not the PCM itself.
    Will continue on Monday.
     
    Last edited: May 9, 2019
  3. Richardsia

    Richardsia Junior Member

    Age:
    64
    Posts:
    3
    Likes Received:
    0
    Joined:
    May 3, 2019
    Location:
    Nevada
    Ram Year:
    1994 - 2010
    Engine:
    5.9 and others.
    Ok, found the short, DEEP in the harness.
    Not sure how two wires so deep in the engine harness get the insulation rubbed off of them.
    Once spliced the alternator works again, gauges read properly, 30A mega-fuse no longer blows, and the transmission does "Total lock up" instead of jerking in and out.
    Two of three codes cleared.

    Still have an error #37, and now the trans does lock-up, but does not unlock properly.
    Stays locked until the engine almost stalls when slowing down.
    I would really appreciate pointers here, do not want to spend another twenty hours chasing a short or open.
    Code and manual are rather vague, it might help to know which module on the trans does what, by location.
     
    Last edited: May 10, 2019

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