Fog lights flash when horn is used?

Discussion in 'Technical' started by DUB, Jan 23, 2011.

  1. DUB

    DUB BRAMIS Photography

    Just wondering if anyone has this happening on their Zeds?

    I've found the wire that feeds the horn is also connected to the fog light feeds. I can't remember ever seeing the fogs flash when the horn is sounding though.:confused:
  2. Benny_C

    Benny_C About as subtle as...

    Hmm, that's not supposed to be like that. It's either a purposely done modification at some stage, or something is shorting between the two circuits/switches...
  3. DUB

    DUB BRAMIS Photography

    It's not happening ATM Ben, I just found the wiring is common that feeds the horn and the fogs, so when I put the dash back in I'll have to check it out.
  4. Altari

    Altari '89 2+2 TT Manual

    Is it a common earth?
  5. DUB

    DUB BRAMIS Photography

    No, there is only one wire that goes to the horn and it is spliced into the fog light power feed too. It's got me scratching my head for sure.
  6. Pregz

    Pregz Ex Z owner

    Maybe a common power feed and the earth wires are switched?
  7. nobull22

    nobull22 Member

    EX cops car??????:D
  8. CHILI

    CHILI Indestructable Target

    Hi Brad,

    As stated by Pregz, the power to the Horn and Foggies can be via the same wire, but the switching to Earth for each item will be necessary before that unit will operate(Horn Button earths out the Horn, Fog Light Switch earths out the Foggies).:)
  9. DUB

    DUB BRAMIS Photography

    I'll speak louder for you Lloyd :p "THERE IS ONLY ONE WIRE GOING TO THE HORN" so I'm confused how it could work when it's common with one of the fog light wires.
  10. aazn

    aazn New Member

    fogs get triggered by a positive.
    horn is a negative.

    maybe something gone wrong previously and an autoelec wired it up that way.
  11. CHILI

    CHILI Indestructable Target

    Can you tone down your voice Brad(I'm trying to sleep here).:p:p

    I was going to give you the answer, but aazn got in first.:D:D
  12. ezzupturbo

    ezzupturbo JDMAutomotive

    the horn has to be triggered by a positive coz its already earthed to the chassis.
  13. Vader

    Vader Just another guy

    Sorry guys, the idea that a single wire goes to two items and operates them independently just won't happen without some complicated one-wire protocol. But that doesn't happen in our cars.

    The steering wheel horn switch controls the earth connection to the horn relay. The horn relay switches battery positive to the horns.

    Both the fogs and the horn have to be switched differently. Maybe the guy that last wired them up got one of the foggies and a horn mixed up? The horn relay has to feed two horns don't forget.

    The more I think about it, the more that idea makes sense. Are they the same connectors?
  14. stumagoo

    stumagoo Active Member

    to add to Vaders comment, the power to the horn will be through the wire from a relay most likely, its earth is most likely through its attachment to the body of the vehicle, my guess is somehow this is the same piece of material tha earths the fog lights, it is my thought that the power must be backfeeding through the foglights circuit as well to light them up.
  15. DUB

    DUB BRAMIS Photography

    You've hit the nail on the head there I think Dave. Ive come to the same conclusion after remembering most zeds have 2 horns and not one like mine. The loom had cut-up wires to the foglight areas and I think I've just mixed up the wires to the foglight with a secondary horn feed. My Zed never had a second horn from when I got it, so I'll be able to plug in a second one now :)

    Thanks for the replies people.
  16. aazn

    aazn New Member

    no the horn is a negative trigger.. you can test this by putting a testlight over it (non-LED) and the horn will trigger.

    i know this because i used to do cruise controls and they used the horn wire.

    BUT im not sure how fogs are wired. as depending weather OEM/AM they can be wired anyway the installer wishes weather its negative or positive.

    factory options does not mean it is installed by the factory, they get a fitter to install it. like reverse sensors, they are sold at dealerships as an option, but are not installed when the car is made. its installed about a day before you get it.
  17. AndyMac

    AndyMac Better than you

    meh only need one...I removed one recently to finish my ducting to the coolers.
  18. DUB

    DUB BRAMIS Photography

    Unless I can get a more manly horn I'm going with 2 units as the existing one wouldn't generate any kind of response above derision, and I need a horn with attitude because there's far too many Camry drivers around my way :p
  19. aazn

    aazn New Member

    if you want a loud horn.. get a air horn.
    get a single horn air horn.. would be loud as hell...
  20. Vader

    Vader Just another guy

    Sorry - wrong. Horns are NOT negative switched. You can see clearly the earth is always connected.


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