Horn Problem

Discussion in 'Touring Models' started by Fossil, Apr 1, 2011.

  1. Fossil

    Fossil Active Member

    I have a 1988 FLTC that I stripped down to an FLHS. For the last ten years I have been having an off and on problem with the horn. I extended the wire to the horn and that fixed it for awhile. Most of the time it has been a grounding problem. I found that the stock ground wire had rusted into. I haven't been able to ride my Harley for a few months but when I had to stop the horn worked fine. Got the bike going again and the same old problem. When I push the horn button I get a 'thump' sound from the horn. I bought a new horn and it still only makes the 'thump' sound. Any ideas as to the problem?
  2. Doug_09ultra

    Doug_09ultra Junior Member

    check to see if there is a small adjustment screw on the back side of the horn. Some of the automotive type horns have them. If there is one, try backing it out a turn and try the horn again. the screw dampens the vibration of the diaphragm and it may simply be too tight. If there is no adjustment screw, try holding the horn button in and rap the horn with a deadblow hammer or rawhide mallet.The diaphragm my simply be stuck.
  3. JBC2565

    JBC2565 Junior Member

  4. lorne

    lorne Senior Member

    can you by pass the switch and put power directly to the horn to see if it is working correctly?

    NEWHD74FAN Experienced Member Retired Moderators

    Because you here the "thump" sound, there is "some" current flowing to the horn. As others have said it could be the diaphragm in the horn is being pulled in by the electromagnet, but the internal "break" switch is not interrupting the ckt to relax it and repeat the cycle rapidly. You can try the adjustment screw, because it is very sensitive, more or less a 1/2 turn or so that will swing from "engage" to louder "buzz to wail" to that "thump". It is also temperature sensitive and such usually caused by aging as switch arm and diaphragm tension weaken over time. If it is the round FIAMM brand type, a suitable replacement may be found at AutoZone, Harbor Freight or O'Reilly's and such for about $15-$20 (if nothing else a test horn), or the dealer for about $90. :53:
    Last edited: Apr 2, 2011
  6. Fossil

    Fossil Active Member

    My Bad!! I replaced the old horn with a new Harley one and the same identical problem is there. Usually when it made that sound I would redo the electrical terminal or the ground wires. I didn't see an admustment screw on the horn.
  7. Breeze3at

    Breeze3at Well-Known Member

    The adjustment screw on my OEM Harley horn was under a dab of silicon.