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Horn Issue

Discussion in '365 GT4 2+2/400/412' started by SouthJersey400i, Jan 19, 2021.

  1. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,333
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    I may have done a post on this issue 5+ years ago but the problem is back front and center again.

    At that time my horn started honking when turning the steering wheel; it got embarrassing! I found that lowering torque on the center steering column nut reduced the problem but it got progressively worse so that I could not torque that nut at all. I did a "temporary" fix and connected the horn wire (a ground) to the unused rear fog light switch. Not a great solution but I seldom use my horn and I could pass NYC inspection.

    AS I posted a few months ago, my light switches had the typical failure of cracked levers. I sent to Verell at Unobtanium and told him to look for a problem with the horn. He found no issue. I just mounted switch today and all of Verell's switch work was good and he installed a new wire to the horn button and looked for grounds of the wire and found none. However, my horn issue remains the same as before. After mounting switch assembly and the three wire connector blocks, I tested lights, wipers, blinkers and horn and all worked. When I installed the key, hub and nut all was okay until the nut took up all the slack in the hub on the tapered shaft. As soon as I applied any torque (by hand) the horn started honking. Each turn of the center nut or the hub produced a HONK. It clearly is not a bare wire grounding, it has something to do with the center hub being tightened on the shaft.

    Has anyone else experienced this or heard of any of our cars having this problem. Since the 308/328 use the same switch I plan to post this on their site as well.

    ANY IDEAS??
    Ken
     
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  3. Part Time

    Part Time Formula Junior
    Silver Subscribed

    Dec 16, 2013
    489
    Port St. Lucie, Fl
    Full Name:
    Gary Shore
    Hi Ken.......so, the horn system is a "ground wire circuit", in that a single HOT wire runs from a relay up thru the column and plugs into the horn button in the center of the wheel. Anywhere that wire touches or grounds out against any grounded part of the column will trigger the horn relay. Something is rubbing a bare spot on the wire, the final contact is when you tighten the nut, something in the column connects to ground. There should not be any final contact between the wire and ground until you hit the button. Put an ohm meter between the end of the horn wire and a good ground and wiggle/press/pull/turn the column and see if you get the meter to move repeatedly with the same movement. Or just disassemble the entire column.
    I haven't had a column apart in years, but it may be as simple as a cracked plastic insulating washer.

    Gary
     
  4. raemin

    raemin Formula Junior

    Jan 16, 2007
    695
    Lyon (FR)
    Full Name:
    R. Emin
    Have you tried to remove the horn button from the column? I've scratched my head with my own horn, and finally realized the bare spade connectors was touching the steering column from time to time. Using a "Flag Connector" instead of a straight one solved the issue. I was lucky the faulty ground was so close: digging deeper in the steering column is a royal pain.

    These are the threads I've bookmarked on the subject

    https://www.ferrarichat.com/forum/threads/cant-find-why-my-horn-barely-works.378651/#post-141661651
    https://www.ferrarichat.com/forum/threads/momo-horn-button-repair-help.563885/#post-145668997
    https://www.ferrarichat.com/forum/threads/horn-pushbutton.433572/#post-145409736

    You could try a search using Horn & Brush as keywords
     
  5. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,333
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Raemin
    The three links you included all referred to horns NOT working, mine works too good! However, in the first link there was a post from someone who's horn honked when turning the steering wheel. That is exactly how mine started (5 years ago). My issue has nothing to do with the button; my horn honks with the steering wheel and button not on. All I have to do is slip the short wire thru the hub, put the hub on and tighten the center nut (I have the correct tool). As soon as the nut gets a bit more than hand tight which means the wheel turns a bit when tightening....the horn honks!

    Gary
    You are on the right track there is obviously something grounding when it should not. However, the function is not as you indicate. There is NO hot wire in the harness and switch for the horn. The wire all the way from the button, thru the rotor/disc, thru the harness to the connector in the dash is all one ground circuit that goes to the horn relay. That circuit must be isolated from any ground until you push the button which creates a ground. The rest of your comments are valid, now to find where that ground fault is and why tightening the center nut causes it to ground.

    I'll be back in the garage today. I expect somewhere on the disc with the brush something is broken or worn out causing the ground when compressed. It may even be grounding against the steering wheel hub in which a case a fiber washer might solve my problem but that seems to easy. I am hoping Verell has some ideas today since he has these switches apart all of the time. More to follow.
    Ken
     
  6. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,333
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Raemin, I forgot to mention I sent a message to the guy that had the issue turning the wheel.
     
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  8. raemin

    raemin Formula Junior

    Jan 16, 2007
    695
    Lyon (FR)
    Full Name:
    R. Emin
    #6 raemin, Jan 20, 2021
    Last edited: Jan 20, 2021
    Former president of F400Club had the very same issue (the horn would be triggered when turning the wheel). it was related to the brush holder, hence my suggestion for the horn+brush keyword search.

    My Issue also was unsolicited random noise, but not related to the steering wheel position. I've copied the photo on the previously mentioned thread and highlighted my problem. When connected to the center pin (in green) the uninsulated female spade connector may touch the steering column from time to time.


    I've replaced this straight connector with a "Flag connector", so as to clear the wire away from the metallic frame of the steering column. This solved my issue.

    Note that I do have the newer buttons (with smaller prancing horse) and the design is improved compared to the inlustration: much better ground. Central pin is also different, but you get the idea.
     
  9. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
    1,333
    Romulus, NY (Finger Lakes)
    Full Name:
    Ken Battle
    Do you believe in MAGIC?? I don't but my issue is fixed without doing much of anything. Either the ground point is very close tolerance or I will be dealing with this again before long. Here is what I did:
    • put hub on column without the key in the keyway and tightened the nut
    • rotated the hub which rotates the horn disc (and blinker kick back) but not the steering column (wheels were on ground)
    • II got no horn honks so this told me the issue was the rotation of the horn disc but rather rotation of the steering column
    • I pulled hub back off and looked at the fixed wire under the horn disc and poked at it and maybe pushed closer to the disc.
    • Then I slightly pinched the two brass tabs at 9 and 2 o'clock (see pic) that were protruding a bit and might have been contacting the metal hub??
    • Reinstalled key, hub and torqued nut quite tight and rotated hub and NO HONKS!
    • I finished installing steering wheel and horn button and all is working; it only honks when supposed to.
    It seems the only thing of consequence I did was pinching the two clips but rotating the hub without the key in place seemed to do something.
    Image Unavailable, Please Login

    Thanks for all your help and ideas. I hope I will not be restarting this thread in April when I am back on the road.
    Ken
     
    raemin likes this.
  10. Ak Jim

    Ak Jim F1 Veteran
    Rossa Subscribed Owner

    Dec 23, 2007
    5,317
    North Pole AK
    Glad you got it fixed. On the 365 the wire for the horn comes up thru the hollow steering shaft. Looks like Ferrari changed when they started making the 400s.
     

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