Peterbilt 379 3406e 5ek no cruise or jakes

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Thegeneral09, Jan 21, 2020.

  1. Thegeneral09

    Thegeneral09 Bobtail Member

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    Feb 19, 2018
    Illinois
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    95 peterbilt 379 with a 5ek 3406. Have no high idle, cruise, or Jake's and according to the scanner, all switches are working, ecm shows accel mode when the high idle is held..... kinda at a loss.... pinned the wiring at the ecm and everything appears fine. Is it possible for someone to have locked cruise and Jakes out in the ecm itself?
     
  2. Opendeckin

    Opendeckin Light Load Member

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    May 20, 2018
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    The clutch switch is almost certainly the culprit. Try pulling up on the clutch pedal while trying to set high idle.

    If not that it could be the brake switch.
     
    Last edited: Jan 22, 2020
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  3. Thegeneral09

    Thegeneral09 Bobtail Member

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    Feb 19, 2018
    Illinois
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    Clutch switch is good....brake switches are good... and ecm shows them working properly
     
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  4. Deere hunter

    Deere hunter Medium Load Member

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    I agree , clutch switch or bad wiring harness. Common on that old of truck!
     
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  5. Opendeckin

    Opendeckin Light Load Member

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    Just because the computer says so doesn't mean it's true.
     
  6. Chubby Fly

    Chubby Fly Light Load Member

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    Ring since you said high idle and cruise not working as well, I don’t suspect at all any of the companants on the motor side. Engine harness does not control the cruise and high idle and Jake switch. You will want to check the truck main harness
     
  7. Rideandrepair

    Rideandrepair Road Train Member

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    How do you know the clutch safety switch is good? It controls cruise/jakes switch. Did you test the switch itself? I just put the two wires together, bypassing the switch. See if cruise/Jakes work. Same with brake switch.
     
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  8. Thegeneral09

    Thegeneral09 Bobtail Member

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    Feb 19, 2018
    Illinois
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    Both... and ecm reads it on/off with clutch pressed/released
     
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  9. spsauerland

    spsauerland Road Train Member

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    Have they ever worked for you?
     
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  10. Thegeneral09

    Thegeneral09 Bobtail Member

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    Feb 19, 2018
    Illinois
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    No.... just got truck roadworthy as it was sitting... and couldn't get an answer ot of the guy I bought three truck from
     
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