Horn Gremlin

[fblanchard]

Hi experts.

The horn of my 1969 280SL sounds unexpectatively when turning the steering wheel either left or right side.
Sometimes going to the end of the course sometimes at the beginning.
Thinking the problem was just behind the horn ring I dismanteled the steering wheel and cheked.
Two of the three little rubber bushings were used and the horn ring was a bit loose and noisy.
So I tried to fix it whith a bit of black silicon paste and indeed it worked for the noise of the ring. But not for the horn.
Then I disconnected and isolated the plus wire going to the horn ring but the problem continues...
Last weekend I dismanteled further and found nothing wrong to my eyes (see photo).
I fear the problem is deeper.
Do I have to dismantel the column further ? And if so how to do it properly ?
Do I have to check somewhere else ?
Anyone has any idea ? Already experienced this king of gremlin ?
Thanks by advance for help.
Regards
Fred from Noumea  

[Paul & Dolly]

Have you tried searching on the site for horn problems ?
There are various different steering wheels fitted, and not all the parts are interchangeable.
I do remember a post , this year, regarding a similar problem when an incorrect part had been fitted to the steering wheel assembly.

Good luck

Paul

[fblanchard]

Thank you Paul.

Yes I made a research with horn and read two pages of horn problems.
I saw the thread concerning a capricious horn with a new steering wheel.
It was mentionned a problem of thickness and then premature electrical contact.
My problem concerns an original steering wheel and occured whithout any obvious reason. I did not change a thing...
By the way I went to work today with the car and nothing happened so far

Fred from Noumea.

[garymand]

ur problem is we don't know which wheel you have.  And now that you have it so dismantled, we must assume you still have unexpected horn sounds?  Seems wrong, but if you ground clip the horn wire (in this dismantled state) the horn should sound dependbly each time you connect ground to the horn wire.  Let us know the syptom now and which wheel.

[fblanchard]

ur problem is we don't know which wheel you have.  And now that you have it so dismantled, we must assume you still have unexpected horn sounds?  Seems wrong, but if you ground clip the horn wire (in this dismantled state) the horn should sound dependbly each time you connect ground to the horn wire.  Let us know the syptom now and which wheel.

So I'll be more precise

First here is my wheel whithout horn pad.
The second photo concerns the isolated plus wire.
At this stage I put the wheel back and drove. The horn sounded again.
I conclued that the problem was beyond the visible wires so I dismanteld further and found nothing wrong as I said.
I then took the first photo of this thread and asked for help. Of course at this stage no horn could be heard and no driving obviously possible neither.

The sense of my question is do you think I might go further in the direction column ? Is it difficult ? I can see no screw. Do I have to take off the under dash pads to access further ?
Do you know another spot where the horn wires may be in contact with the direction ?
What is evident is the relation between the movements of the wheel and the horn.


Yours sincerely

[garymand]

My experience is with a 250 collumn.  Its not the same, but I understand the problem now.  the 69 seems more involved.  Ithe is a horn lead that comes up along the collumn.  It is iprotected nside a steel wire tray on the 250.  The wire connects to a commutator ring and your steering wheel rotates a 'brush' of some kind that wipes on the ring as you turn the wheel.  I don't see that you have exposed the contact ring in the photos.  You need to go deeper by taking the nut of the shafta and 'pulling the hub off.  the hub apparently has a connector that carries two wires: a good ground and the horn negative lead. 

The horn sounds when you connect the horn negative to ground.  so, I'm thinking the problem is near the horn ring.  probably the brush is broken in some way that allows it to contact the ring and ground, or the horn wire has frayed insulation and the wheel hub is touching the horn wire sometimes as it is turned. 

You have to take the dash apart to drop the collumn, but that's not where the problem is, theres no way for the rotaing hub or shaft to contact the hoprn wire, because it runs doon the outside of the collumn away from the shaft.  Correct?

[fblanchard]

Thank you Gary this helps.

In my first message I took the the photo of what you call "brush" I think.
When I inspected the two little contacts there was a very little piece of unknown material between the plastic support and one of the two metal brushes.
Did this block the contact on "on" position or made a short between the two brushes ?
First I did not pay attention to it but whith what you say and driving now without sound
Soon I'll go further down the column and let you know.

Regards
Fred from Noumea
 

[garymand]

you found it.