Broken City Horn..

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Hanadarko, Jul 31, 2010.

  1. Hanadarko

    Hanadarko Independent Owner/Operator

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    I started troubleshooting my broken city horn. Found out there was no relay in the panel for it. :biggrin_2556: - Replaced that for $12.

    Still no horn.

    When I press the center horn button on the steering wheel, and feel the relay at the same time , there is no click.
    So at this point, since i know the relay has power - I am suspecting the horn button or contacts or wiring. If i had a schematic I could possible jump the relay and see if the horn actually works. But without any click from the relay, I know that's the 1st place to start..

    So, how do you disassemble the center of the steering wheel (plastic KW logo cap)? - I dont want to ruin it by warfing it out of there...

    :biggrin_25523:
     
  2. heavyhaulerss

    heavyhaulerss Road Train Member

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    well this probably has nothing to do with your problem, BUT, one time I tried my horn & it did not work. looked at fuse, it was good. I had no click either. I went to replace horn itself. took front grill off & no horn at all. it was not there, though the wires were. then I thought a min & then called the shop who just installed my new radiator 2 weeks earlier & asked if they removed my horn during installation & forgot to put back on? after a couple minutes on hold, shop man aswered back, YEP it is right here on the shelf. :biggrin_25523: that just showed me I need to do my pretrip fully & I would of caught this sooner instead of over 2 weeks later, & of course to check work of any shop on my truck. the shop was & is a good shop. I still use them, just one of those day's. sooooo if anyone was workinmg anywhere nearby your horn, wires to the horn, you may want to start there.
     
  3. mslashbar

    mslashbar Light Load Member

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    The center cap on your steering wheel just pops off. Stick a small screwdriver under the edge and just pop if off. The button usually works off ground, not power.
     
    Hanadarko Thanks this.
  4. Waterman1000

    Waterman1000 Light Load Member

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    I agree with heavyhaulerss . If your horns still there test them with a hot jumper wire to see if they honk. As to the relay. Depending on how many prongs. You could try and jump them or use a cont light to if the wires are good. Your horn button might be ok. I was "faked" out one time after pulling the dash to track down a bad part and it wasn't in there;)
     
  5. Hanadarko

    Hanadarko Independent Owner/Operator

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    The horn is present. Dunno if it works or not yet. No click from the relay and w/o any decent wiring diagrams, I cant tell which pin is what.

    But I got worse issues to deal with at the moment.. (Battery in another thread...)
     
  6. Smalltruck

    Smalltruck Light Load Member

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    Most trucks are wired the same so here goes.....
    The horn should be hot all the time. The horn button provides the ground when you push it in. So if you ground the center wire and the horn blows the problem is in the horn button on the column. If it doesn't you get to backtrack....
     
  7. Hanadarko

    Hanadarko Independent Owner/Operator

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    Ok. Makes sense. So the relay just provides a ground to the horn?
    I would have thought the opposite I guess. All of the examples on the NET show it with constant ground and APPLIED + when you activate the relay

    Pull the relay out and apply ground to the center pin?
     
  8. mslashbar

    mslashbar Light Load Member

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    Actually, I think the ground from the horn button trips the relay which sends power to the horn.
     
  9. Heavyd

    Heavyd Road Train Member

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    Most relays will have a little diagram on the side showing how they are pinned. All relays are pinned the same with the same numerical layout. Normally battery power is at pin 30. The horn will get its power from the relay by closing contacts between 30 and 87. Try to see if there power at pin 30, and try to jump pin 30 to 87. Even if the relay is closing the ground side or hot side, by jumping 30 to 87 should make the horn work. If not, see if there is power at 30. If no power at 30, find power somewhere else and jump to 87 and see if it works.
     
  10. Hanadarko

    Hanadarko Independent Owner/Operator

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    Thats what I'm thinking....none of the schematics on google show a ground being applied to the horn, only a +.

    Either way, once I ohm out the relay (I can close it with a 9v battery) then I can figure out what pins it closes and jump it that way...

    :biggrin_25525: