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Horn sounding while cornering. Intermittant fault

Discussion in 'General Mercedes-Benz Related Discussion' started by McDonald, Aug 26, 2018.

  1. McDonald

    McDonald Senior Member

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    Joined:
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    Location:
    Surrey
    Your Mercedes:
    SL500 2004
    Curious thing has happened today, and a couple of random times recently. While cornering sharply but at low speed, the horn has sounded - by itself - without my touching it. Why would that happen?
     
  2. CJD

    CJD Active Member

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    Sep 25, 2017
    Location:
    Bourne
    Your Mercedes:
    C200 AMG Line, Premium Plus, S205 Estate, 2018
    I don't know for sure with Mercedes, but it's a know problem with Porsche, that the springs in the steering wheel / horn can get weak and this can lead to the horn sounding by itself.
     
  3. Srdl

    Srdl Senior Member

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    Location:
    Hampshire
    Your Mercedes:
    GLC43 AMG 2018 (X253) Premium Plus
    A worn cable shorting while the steering wheel is on a tight lock? That’s a pure guess so some of the techies on here may have a more educated view.
     
    McDonald likes this.
  4. OP
    McDonald

    McDonald Senior Member

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    Your Mercedes:
    SL500 2004
    Thanks CJD. So far it's just a short parp and stops as I turn the wheel back towards centre, but I can imagine it becoming and endless blast and an embarrassing scene ensuing.
     
  5. LostKiwi

    LostKiwi Senior Member

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    Location:
    Midlands / Charente-Maritime
    Your Mercedes:
    '93 500SL-32, '01 W210 Estate E240, 02 R230 SL500 (Malcolm Spec), 04 Smart Roadster Coupe
    On most cars the horn is permamenity wired to 12v and switched by providing an earth. If the wire from the horn back to the SAM or wheel is chafed you can get that problem. It could even be a bad clockspring.
     
    Srdl, Flyinspanner and McDonald like this.
  6. L John

    L John Senior Member

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    UK
    Your Mercedes:
    W204 C350 Petrol Elegance
    Just go with it, (own it, as they say).
    A shake of the head as you look at the person responding should be all that's needed.
    :D
     
  7. SteveB73

    SteveB73 Active Member

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    Location:
    Sussex
    Your Mercedes:
    S320Long CDi
    I have started having same issue. It also sounds occasionally when using volume controls on the wheel. Did you get to the bottom of this issue? As you say McDonald, it could get kind of embarrassing.
     
  8. thebiglad

    thebiglad Senior Member

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    Location:
    Central France
    Your Mercedes:
    2005 CLK 270 cdi
    There is a device within the steering wheel called a clock spring. It is a rotary component that carries the electrical signals from the steering controls to the cables in the steering column and they do wear and cause erratic results.

    Replacement is straightforward if you buy a brand new component but more tricky if using second hand pieces.
     
  9. SteveB73

    SteveB73 Active Member

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    Location:
    Sussex
    Your Mercedes:
    S320Long CDi
    I’ve since seen posts about this on other forums claiming that there is a repair kit available from Mercedes and that they had the repair done for around £120. However I called Mercedes today and they knew nothing of this? They did offer to sell me a clock spring for 300 quid though. Need to do some more digging. Will take wheel apart tonight and see if there is an obvious problem.
     
  10. OP
    McDonald

    McDonald Senior Member

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    Your Mercedes:
    SL500 2004
    My car is in intensive care (MBS Southampton) as the ABC pump broke. While there the unwanted horn sounding is also being cured. I understand it's the clockspring, but can't confirm that until I pick the car up on Saturday.
     
    John Laidlaw likes this.
  11. SteveB73

    SteveB73 Active Member

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    Sussex
    Your Mercedes:
    S320Long CDi
    I took the wheel off mine Sunday. MB told me it was probably the clock spring but I did notice the springs under the frame behind the airbag were worn and seemed very close to horn push buttons at each corner. I removed the shouldered screws and put a washer behind each to get a little more spacing between the switches and so far have not had any more ‘beeps’ from either cornering or pushing wheel function buttons. Fingers crossed it’s sorted as clockspring is 300 odd quid.
     
    daibevan likes this.

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