2000 Peterbilt 379 brake/cruise

Discussion in 'Trucks [ Eighteen Wheelers ]' started by HosRanch, Jul 7, 2023.

  1. HosRanch

    HosRanch Bobtail Member

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    Mar 6, 2023
    Emory Tx
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    It's a 6NZ, yes it did used to work.
     
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  3. jamespmack

    jamespmack Road Train Member

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    Mar 25, 2014
    OH
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    Need prolink, or Laptop to see status during brake application. You need to see if the ecm sees the signal.

    @Goodysnap is probably typing the same thing currently.
     
  4. HosRanch

    HosRanch Bobtail Member

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    Mar 6, 2023
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    Y
    Yes we had it on the ET and the ecm doesn't see the applied brake.
     
    Oxbow Thanks this.
  5. Goodysnap

    Goodysnap Road Train Member

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    Another common issue is people swap ECMs. Different OEMs can program the inputs to different pins. May need a wiring guru and CAT ET to sort the issue.
     
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  6. HosRanch

    HosRanch Bobtail Member

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    Mar 6, 2023
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    Yes I recently got a new ECM, it was a CAT reman, and all the files were copied over from the old one, I am starting to think the ECM is the problem.
     
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  7. Goodysnap

    Goodysnap Road Train Member

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    If original. Check Pete side wiring harness for brake applied signal wire to match pin location programmed with in ECM.
     
    blairandgretchen and jamespmack Thank this.
  8. Stay Puft

    Stay Puft Bobtail Member

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    Mar 17, 2022
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    My 06 Pete did that same stunt. When I was going down the road with the cruise on and applied the brake it just kept going. It turned out the circuit breaker backed out and fell on the floor for the tail/stop light. Hope this helps.
     
  9. HosRanch

    HosRanch Bobtail Member

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    I appreciate it, I think I am good there because I still have stop and tail lights. I took it Peterbilt and they think as mentioned above that one of the pins is in the wrong spot in the ECM.
     
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  10. HosRanch

    HosRanch Bobtail Member

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    Mar 6, 2023
    Emory Tx
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    Does anyone by chance know what the part number is or what specifically Peterbilt calls this part described (in the quotations) below?

    """"It looks like a brake switch, but it a cruise control switch which knocks off the cruise control when you applied the brakes. Its under the dash, behind the ignition switch. You have to remove the bottom half of the steering column "cover" which is about 6 screws or so. Then look underneath(behind the ignition switch) and you will see 2 wires hook on a round switch. Remove the 2 little screw from the wire and use some channel lock pliers to remove the switch counter clockwise. Its easy and self explanatory was you see it. I've replace 2 of them in two years.""""
     
  11. kwforage

    kwforage Road Train Member

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    Jun 3, 2007
    Wisconsin
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    Did you ever figure it out? I also have a 2000 379 with a 6NZ that doesn't shut cruise off with brake and I have turned the truck upside down looking for a brake switch that I cant find.
     
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