2012 Kenworth Won't Turn Over

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by FarmTrucking4020, Jan 21, 2022.

  1. FarmTrucking4020

    FarmTrucking4020 Bobtail Member

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    Nov 6, 2018
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    I have a 2012 Kenworth with the ISX Cummins. Went to start it this morning and couldn't get the engine to turn over. The starter solenoid will click when I turn the key. Got my volt meter out and had 12 volts at the starter. Switched the starter relay with the horn relay and got the same outcome. Beat the starter with a hammer while someone else turned the key. Turned the key 30 times and shook the ignition switch thinking it could be the ignition. Nothing. Yesterday it did this the first time I tried to start it but turned over the second time I tried. It was 0 degrees out so I didn't think anything of it. The only reason I'm not 100% sure the starter is bad is because a couple days ago it didn't do the "self check" thing where it clicks 8 times when you first turn the key on. It did that about twice that day and hasn't done it again since. Makes me wonder if the ignition is bad. I'd hate to go through the headache of pulling the starter off and buying a new one just for that not to be the problem. Thoughts?
     
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  3. AModelCat

    AModelCat Road Train Member

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    Power at the starter or just at the solenoid?

    Should have 12 volt at the starter solenoid on the little ignition wire with the key in start position.

    If the above is good, should have constant power from the batteries to the solenoid. When you hit the key to start, power should run through solenoid to the other post that connects into the starter.
     
  4. FarmTrucking4020

    FarmTrucking4020 Bobtail Member

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    Nov 6, 2018
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    Just the solenoid. There was no voltage drop at the solenoid when my helper would turn the key to try and start it. Would getting 12 volts to the starter mean the starter is bad, and not getting voltage mean the ignition is bad?
     
  5. Smellfunny

    Smellfunny Road Train Member

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    Jan 28, 2012
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    If you have 12+ Volts at your stud posts on starter and they stay 12 volts when you hit the ignition then you need to move to the solenoid on the starter and see if you go from zero volts to 12 V for the solenoid on the starter to engage the starter drive when you turn the ignition key. If you have 12 volts there when you turn the ignition key and the starter just clicks then the starter is bad. If you don't get 12 volts at the solenoid when you turn the ignition key then you have to move further back. Not sure if that truck has an actual starter solenoid that is on the firewall. This is a video link to one that is probably on a Ford but it is the same setup on most of the older trucks. 2012 Kenworth I have no idea what it has.
     
    Last edited: Jan 22, 2022
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