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reverse polarity jumped...intermittant problem

Discussion in '2nd Gen Tundras (2007-2013)' started by koots33, Jul 5, 2024.

  1. Jul 5, 2024 at 10:41 AM
    #1
    koots33

    koots33 [OP] New Member

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    jumped my 2008 5.7L Tundra with reverse polarity. Yes I actually did it. Send the abuse.

    My problem. It won't start, it did run afterwards for a day.

    No noise at all when ignition engaged. All dashboard lights and devices work.
    Changed battery
    checked fuses

    scanned but with odd results...the scanner scanned and showed no problems...not even my known maintenance warning that should have been there. But the scanner's green/yellow/red indicator lights never lit up suggesting to me that the scanner would not connect properly? I can't understand why it would 'scan' at all if there is an open in the circuit.


    Anyone with magic wand that can suggest where to look?
     
  2. Jul 5, 2024 at 11:20 AM
    #2
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    You may need to replace that main relay. Even if it looks fine from the top, it may be fried. Similar things happened when I changed the alternator on my friend's Camry, while I disconnected the battery he decided to reconnect it to charge his phone. I failed to notice and got some sparks when my screwdriver slipped and tumbled from the top of the engine. After car wouldn't start, but other things were wonky, so I replaced the main relay and went back to normal.
     
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  3. Jul 5, 2024 at 11:27 AM
    #3
    shawn474

    shawn474 Lego connoisseur

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    ^This would be the first thing to check
     
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  4. Jul 5, 2024 at 5:03 PM
    #4
    Canman

    Canman New Member

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    I checked in a Google search to see if the Tundra has a fusible link, and it seems it might depending on some options. With my 97 LX450, it’s the first thing to go when stuff like this happens. Might suggest to see if you have one, and if so, make sure it isn’t fried.

    555794A0-07AD-4064-8DC0-C5A6803D140D.jpg
     
  5. Jul 6, 2024 at 7:47 AM
    #5
    koots33

    koots33 [OP] New Member

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    thanks for the input. I believe the main relay is ok. I swapped it out with others to no avail. Everything electrical seems to work EXCEPT the starter.....and it did work for a day (9-10) times the truck started and ran as normal. The next morning I was back to nothing when ignition engaged.

    Some suggest that this is indicative of starter/starter solenoid problem.

    I am of course concerned about control circuit boards too.
     
  6. Jul 6, 2024 at 4:27 PM
    #6
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    Pull that starter relay and jump it with a wire or paper clip. This will sorta narrow down the problem.
     
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  7. Jul 8, 2024 at 9:46 AM
    #7
    koots33

    koots33 [OP] New Member

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    Jumped the contacts for the starter. Nothing. Voltage present.

    makes me think starter solenoid, or control board, or bad wire. Damn.

    thx
     
  8. Jul 8, 2024 at 1:17 PM
    #8
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    Then the starter may be dead... Not sure how you jumped it, since there is specific teeth that have to be jumped, but it's been a while for me. These new ones I probed all 4, lol. Since I got a click and that was it, I convinced myself it was the starter.
     
  9. Jul 9, 2024 at 1:08 PM
    #9
    koots33

    koots33 [OP] New Member

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    blackdemon, I shorted the starter relay contacts with the relay removed. Nothing. Not a sound.

    I just pulled the fusable link. I tested it all over for continuity and it seems fine. Not even sure how this fusable link is designed though. Not sure if I should replace it anyway.

    Here is the full story:
    truck batter found low, I think the interior light was left on, would not start.
    Jumped it with a spare batter in REVERSE POLARITY (insert kick to the head here!). Left on for 4-5 seconds. melted jumper cable handle
    Left truck overnight.
    Medicated.
    Truck would not start in the morning. All electrical is fine on ACC. when ignition ON there is nothing...no click or anything.
    The truck sat in the heat all day, about 5 pm I tried it again and it started and ran as normal!?! Ran some errands and turned truck off and on about 10-12 times that evening.
    Next morning truck won't start. Again all electrical operated on ACC but no sound and no ignition when key turned to IGN.

    The fact it ran and I looked over and tested everything pretty good and took it on the hwy for 10 km is confusing to me. Why would it start and run fine then stop again at random? brittle or burnt wire possibly?
    Electronics are not usually intermittant issues. They work or don't. Agree?



    removed and load tested battery. Battery is good. Also tested batter that was used to jump start. Also a good battery.
    12.5v at battery terminals, hot to ground terminal, hot to fender, hot to motor
    all fuses checked
    **jumped starter relay contacts, small arc, nothing from starter, no sound. ** if starter is good, shouldn't this have engaged the starter? It didn't which leads me to believe it is the starter but I admit to knowing nothing.
    fusable link is removed but I can't see anything odd and seems to meter out just fine.
     
  10. Jul 10, 2024 at 7:07 AM
    #10
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    Does sounds like the starter is completely dead, or wiring is fried in between the relay and the starter.
     

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