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Grounding And A Horn

Discussion in 'Flat Fender Tech' started by Buster1, Sep 27, 2021.

  1. Sep 27, 2021
    Buster1

    Buster1 Member

    Ft Worth
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    Aug 8, 2021
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    50
    Hey guys,

    So I’ve tried almost everything I can think of. I’ve got a modern style 12V Hella horn I've been trying to get installed for the first time on my 12V M38. I think I need a better grounding location for it.

    The horn works great connected straight to the battery (scared myself good on that one).
    The horn button works.
    Re wired everything too.
    Even tried just connecting the wires at the dash without the button.
    Fuse on the block is fine. The block sends power to other components straight from the battery. (Unswitched block).

    But when I attempt to sound the horn, it just goes “squeek” and makes kind of a click chirp sound. Nothing. I’ve got around with my good multimeter too, with the positive on the positive battery terminal, and touching my other grounding locations and bolt heads around the engine and firewall... and I’m getting no DC current flow. I’ve touched the negative lead to all sorts of places and no current flows from the battery.

    Do you have any ideas? Am I doing something wrong? I feel like my Jeep won’t ground maybe, is that possible? Do horns have to be grounded to the battery neg?

    Thanks.
     
  2. Sep 27, 2021
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    Nov 22, 2003
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    Where are you mounting it to? Is your jeep wired to switch power to the horn or completing the ground to sound it?
     
  3. Sep 28, 2021
    Buster1

    Buster1 Member

    Ft Worth
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    The horn is temporarily mounted to the firewall. That shouldn’t matter... right?

    My Jeep has a 4 prong fuse block that is powered straight off the battery +. The button switch, and then horn are connected to one prong on that. I have a - ground coming off the horn and have tried grounding that to many different places, including another grounding location that has a different lead going back to the batt -

    Thanks for the help.
     
  4. Sep 28, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Hills of NH
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    Horns are very sensitive to needing full voltage, and plenty of amps. They need good wiring and maybe even to have the engine running. Possibly yours needs a slight adjustment, since it works direct from the battery. There should be a screw adjuster on it, possibly sealed.

    Another pro-tip... they won't work right if mounted rigidly. They need to be able to vibrate, on a rubber or flexible base.
     
    Last edited: Sep 28, 2021
    Downs likes this.
  5. Sep 28, 2021
    Twin2

    Twin2 not him 2021 Sponsor 2020 Sponsor

    Virginia Beach, VA
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    very true
    and OP didn't say if he was operating horn with 12V or ground with push button switch or horn button on wheel
     
  6. Sep 28, 2021
    Buster1

    Buster1 Member

    Ft Worth
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    Thanks guys. I’m also starting to think I might need a horn relay, as the button/switch may not be able to handle the power load. But even when I remove the button and try touching the wires there... nothing.

    Twin2, I’m not sure what you mean. I have a new Oreily basic button with the rubber cap, mounted on the dash panel. No horn on the steering wheel. The button is set to connect the 12v circuit when depressed.

    Here’s how I’m currently set up.

    46112F90-9BEA-4993-90D0-8107EE6FAFC3.jpeg
     
  7. Sep 28, 2021
    Twin2

    Twin2 not him 2021 Sponsor 2020 Sponsor

    Virginia Beach, VA
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    just a example of mine . two connections on horn
    Red is 12V - always hot
    Black is grounding wire to steering wheel
    no relay required
    as pete mentioned horn can not be mounted solid . must beable to vibrate
    CAM00431 - Copy.jpg
     
  8. Sep 28, 2021
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    Are the wires original from the po or new? If older check for corrosion / fraying at the connectors.
     
  9. Sep 29, 2021
    Buster1

    Buster1 Member

    Ft Worth
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    Update: I tried a different horn I just received in the same setup... and it’s works perfectly! I’m not going mad after all!

    I’m guessing the old Hella was just being finicky about having perfect volts or something, as it worked when checked on the battery leads.

    Thanks guys!
     
  10. Sep 29, 2021
    boopiejones

    boopiejones I can’t drive 55

    California east bay
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    my guess is that the original horn will probably work fine with a relay. Regardless, horns pull a lot of amps so a relay is probably a good idea.
     
  11. Sep 29, 2021
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    cordele, Ga.
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    Some of these horns are polar sensitive. They are marked + -.
     
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  12. Sep 29, 2021
    ojgrsoi

    ojgrsoi Retired 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Weatherford, TX
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    Whoever gave you the free horn needs a kick in the butt.
     
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  13. Sep 30, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Hills of NH
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    Possibly the original needs a slight adjustment. Look for an external screw/locknut, which sometimes may be 'sealed'.
     
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