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Horn Wiring

Discussion in 'Bay Tech Clinic' started by Stuvada, Apr 20, 2020.

  1. Stuvada

    Stuvada New Member

    Messages:
    27
    Location:
    Perth
    My 72 transporter has an under dash horn button and has been wired from fuse to switch to horn then to earth. i.e. +ve wire switched.
    I want to wire the original horn button on the steering wheel but am having trouble understanding the wiring. It seems that the -ve wire is switched. i.e. from fuse to the horn then horn to horn button then to earth. Correct? If that is so how does the wire inside the steering column connect? And where to? How does the wire not get twisted and break? How is the horn button effectively earthed? Any assistance is appreciated.
     
  2. Luna76

    Luna76 Active Member

    Messages:
    54
    Location:
    Gisborne, Victoria
    Syncro27 likes this.
  3. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    3,731
    Location:
    Seven hills
    The brown horn wire that goes down the inside steering column shaft goes through the rubber coupling center and turns sharply ,and sits between the rubber coupling the metal coupling flange.
    There is also a second brown wire. Which goes from the horn to the base of the external steering column,there should be a push on terminal on the base of the external steering column. The metal cover plate that you see on the inside of your car at the base of the steering column as it goes through the floor. Well it has a metal loop on the inside of that which the wire goes through before it connects to the bottom of the external steering column wire terminal.To keep it at of way turning steering shaft.
    The horn is earthed when the button on the steering column is pressed making the final earth contact between the inside shaft and external shaft.
    If you can get all this connected up you may realise why people bypass the original set up and put another push button elsewhere.
    Has your steering column been out before? As there should be a plastic insulating ring between the external steering column and the ignition housing,if this is in wrong place,the horn will remain on all the time due it being earth constantly.
    The wire terminal on the bottom of external column may also be broken off,which is sometimes why it gets bypassed.As once you get the wire onto this terminal you are meant to bent it upwards to make sure it is clear of the steering shaft as it turns.
     
    Syncro27 and Mordred like this.
  4. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,895
    Location:
    Penna, Hobart
    The diagram in the post above is the early version steering column which you should have with the 72. The post 74 doesn't have the plastic grommet at the bottom and has a different wiring setup altogether, including a link cable between the steering column shaft across the rubber flexible coupling which is not to be added in the earlier ones. This is more for others looking at this post later and getting even more confused. I reckon the designers tried to make it less complex in the later years.

    Adrian
     
  5. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    3,731
    Location:
    Seven hills
    I don't know how in manufacturing in the earlier models how quickly they could put the wire on the bottom of the external steering column,it is a right pain in the bum. It must of got back to higher management that it's taking to long to connect.
    You would have to be related to Houdini to almost put it on.:(
     
    David H likes this.
  6. Stuvada

    Stuvada New Member

    Messages:
    27
    Location:
    Perth
    Thanks to all for your contributions. Very detailed information. Hopefully I can follow this and trace the wiring and also look for the insulators that may have been removed at some stage. It is now clear that the inner shaft and outer casing are not insulated from one another and both carry the circuit back to the horn button.
    I am now trying to get my head around the insulation between the outer shaft and the indicator switch housing. I note that the plastic locking ring at the base of the outer casing is the insulator at the floor. It is obvious that the rubber sleeve between the outer casing and the main steering bracket is also an insulator. It would be nice to have it back to original.
     
  7. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    3,731
    Location:
    Seven hills
    The plastic insulator (#11 in charts above) in the housing which you can't see it unless it's apart from each other. Have you got one?
     
  8. Stuvada

    Stuvada New Member

    Messages:
    27
    Location:
    Perth
    Wayne, it appears that I don't have the #1 plastic insulator part. I have 3 steering columns but none of them have the insulator. Is that fitted on the inside or outside of the outer casing to insulate the indicator switch housing assembly. I'm guessing on the outside. Do I need it? Can I use something else?
     
  9. Wayne murray

    Wayne murray Well-Known Member

    Messages:
    3,731
    Location:
    Seven hills
    If you can find something that is a thin plastic,could work. There isn't a lot of room between the two,outer column and ignition housing. I have heard not from my personal experience if part #11 wasn't there,once all connected and power connect the horn will be sounding all the time with out pressing horn button.So I take it that yes you do need it. It fits over the external column and fit into the inside of the ignition housing where the shaft goes through.
    Are all your three ignition housing and steering column from 72. As interchanging them will only work one way ,doesn't work the other way around )as I found out column and ignition housing are different sizes.
    I could check over the week end I may have a spare part #11 I could post to you on Monday if your willing to pay postage which I couldn't image it costing the earth,a kidney may be;)
     
  10. Stuvada

    Stuvada New Member

    Messages:
    27
    Location:
    Perth
    Found one!!!!! Was in the junk pile all the time. Just didn't know what I was looking for. Thanks for the offer anyway. Hope to have it all wired up tomorrow.
     
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