Train horns kill my cruise control!!

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by SemperFiServices, Aug 19, 2020.

  1. SemperFiServices

    SemperFiServices Medium Load Member

    Jan 29, 2013
    Indianapolis, IN
    This weekend I installed my Nathan K3LA locomotive horns on the crossmember just behind the cab of my 2015 Prostar, facing backward. I ran the 1/4" air line from the electric solenoid, to a brake relay valve I have on an additional 8 gal air tank I mounted under the cab, which goes to the horn via 1/2" air line. So the horn works just like stock, but a helluva lot louder.

    But when my cruise is set, and I hit the horn, my dash lights up with the triangle, abs, and traction control lights, and that combination always kills your cruise until you shut the truck off for 5 mins.

    So any idea why it's doing this? I added the 3rd tank so I wouldn't drain the primary or secondary tanks, but the 3rd tank feed is directly off the air dryer, so I don't know if the sudden drop in only a few psi is causing the abs to trip up ir what? I don't run around like an ####### blowing my horn for fun either, I just want my darn cruise to work right. I'd appreciate any advice y'all can offer!
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  3. Chinatown

    Chinatown Road Train Member

    Aug 28, 2011
    Henderson, NV & Orient
    Maybe something like when there's a loud thunder during a storm or loud fireworks, that set off car alarms all over the neighborhood.
    Vibrations or recoil from the train horn you have.
    SemperFiServices and Snailexpress Thank this.
  4. SmallPackage

    SmallPackage Road Train Member

    Dec 20, 2019
    Marion Texas
    I’d guess the noise and vibration is interfering with the speed sensor on the tranny. By your discription it sounds like those horns are mounted close to it.
    Just a suggestion since train horns are kinda considered by some to be illegal. Power them by a seperate switch or valve than the factory ones so you don’t hit them during an inspection. Trooper may make you remove them and give a ticket for in operable factory horns.
    I love train horns and have them hidden on all my trucks but I have them as a seperate accessory. Cya!
  5. Goodysnap

    Goodysnap Road Train Member

    Jul 12, 2017
    You lost me at International and train horns? Is that even legal.......?

    Just out of curiousity what faults are logging in the ABC/TCS system? I would start there.
  6. lwlevens

    lwlevens Medium Load Member

    Feb 9, 2018
    If it keeps up ace the horn easy fix!!!
    SemperFiServices Thanks this.
  7. StrokerTSi

    StrokerTSi Medium Load Member

    Aug 28, 2016
    Probably cause you sourced the air line from the brake relay valve and a sensor senses an unexpected drop in line pressure.
    AModelCat Thanks this.
  8. buddyd157

    buddyd157 Road Train Member

    May 25, 2017
    under a shade tree
    'bout as legal as aircraft landing lights?
  9. not4hire

    not4hire Road Train Member

    May 16, 2012
    Sounds like a similar problem cousin Eddie has...

    spsauerland and Goodysnap Thank this.
  10. Final Drive

    Final Drive Road Train Member

    Jan 21, 2015
  11. Brettj3876

    Brettj3876 Road Train Member

    Nov 18, 2014
    Canceling cancel culture/CCC
    Haha thanks I needed a good laugh and almost spilt coffee on my nards
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