Horn / steering coupler grounding

[dakazman]

  Thanks to SilverBeast 
    I ran a quick test for continuity from the steering column shaft to the lower steering coupler, thankfully not when installed. I found the coupler safetied as pictured, the coupler is in 3 distinct pieces      and will not ground when safetied in this way.
 I also show how to safety it to carry the ground.
Dakazman

[SilverBeast]

I thought I read somewhere that there was a wire (presumably with two ring terminals fitted) fixed under the nut/bolt heads to give continuity across the universal joint (flexible coupling on S1/2's ?). I've just been looking on-line but can't find any evidence of this now of course! I know there are one (or two) fitted from the rack to ground the electrics in the front compartment so I may be confusing it with those.

[dakazman]

  Here are some better pics and a schematic breakout of where and what we're trying to accomplish.
I have also seen a metal flex plate joining the two in other applications.  Hoping the thru bolts as pictured touch inside the center plate is not a good ground as the previous method of safeting showed.
   It not a safety wire for the bolts primarily as a secondary, yes.
Dakazman

[jbcollier]

Yup, they came stock with a wire from one side to the other.

[jbcollier]

#5 - ground strap

https://mossmotors.com/steering-rack-2

[GavinT]

I dunno, D'man.
Does this count as a 'good connection' ?

[Clifton]

Thanks for posting this. It seemed strange I have ground that could provide the amos for a horn. I ran a relay instead. I'll ground strap it and ditch the extra relay.

[dakazman]

Gavin, that would work if it’s on both sides of center plate.
Dakazman

[RafM]

I've just finished rewiring my car, I don't have an earth strap across the UJ but as soon as I put the steering wheel in place the horn sounds and won't stop!

A bit of fiddling around needed perhaps.

[SilverBeast]

I've just finished rewiring my car, I don't have an earth strap across the UJ but as soon as I put the steering wheel in place the horn sounds and won't stop!

A bit of fiddling around needed perhaps.

I had similar,  intermittently. It could be you haven't extended the column enough before tightening the clamp so the outer on the steering boss is shorting to the contact on the column, or the steering column bushes are worn and allowing the column inner to do the same.

[dakazman]

  Another thanks shoutout to Rafm.
 I went through rebuilding the column as it was when I got it. I am missing 10-13 , which makes it difficult to get a idea where your picking up contact . Is your horn button stuck in, mine has a spring in it .I assume that my PO had a problem with the horn also hence all the missing parts.   
 

[SilverBeast]

Your horn button is different from mine, you have a spring loaded contact to transfer the ground between the button assembly and the column outer. Mine (73 TC) has a piece of bent brass from the bottom of the horn assembly. It was disconnected when I got it and wired to use the fan switch on the dash (fan fitted but disconnected!).

The extension assembly lock block (so the column can collapse in an accident rather than spear you - though I suspect that would be the least of your problems if you've bent the front T of the chassis that far) should be below the outer column so shouldn't be anywhere near shorting inner to outer there. It shouldn't matter anyway as the contact ring on the column should be isolated from the outer column and connected to the horn via a wire from that.

[dakazman]

   This is a perfect place for “Murphy “ to run a ground wire and not at coupler. However it will turn with steering wheel.
 Also if the plunger stuck the horn would both shut off.
   I added the schematic difference in some breakout drawings I did .
See pic
Dakazman

[dakazman]

Rafm , if you disconnect the PB purple/black at this connector does the horn stop?
Dakazman

[RafM]

  Another thanks shoutout to Rafm.
 I went through rebuilding the column as it was when I got it. I am missing 10-13 , which makes it difficult to get a idea where your picking up contact . Is your horn button stuck in, mine has a spring in it .I assume that my PO had a problem with the horn also hence all the missing parts.  Silver mentioned the extension assembly lock item 4 , it may be grounded there.

TBH I'll get around to it sometime soon, after fitting a new loom it's the only thing that's not working properly so I'm pretty happy.

I have the parts you were missing, a horn 'pencil' and the cage to hold the horn push, my steering wheel has a brass, spring loaded ring that makes contact with another brass ring on the main column, which I assume maintain continuity. Hopefully a bit of tinkering will sort things out.