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[Jim G]

Hi all,
So I fitted an aftermarket steering wheel to my TR4. Being reasonably tall, the smaller aftermarket wheel helps with leg room - now I can actually get my legs under the wheel without the blood flow to my feet stopping.
Question: for some reason my horn now sounds intermittently and of its own volition when I turn slightly to the right.
Clearly a short somewhere but does anyone have any thoughts where it might be happening? I've checked everything I can see around the column and associated wiring but can’t see anything obvious.
Annoyingly, sometimes the horn push doesn’t activate the horn, sometimes it does...
Its driving me nuts!

TIA

[bobhustead]

Unlike most switches that connect the device to power when you throw the switch, the horn switch connects the horns to ground. The wire going to your horn push is grounding someplace outside the intended circuit.

Bob Hustead

[charley fitch]

Well Jim you are not the only one that has the exact same symptoms with the horn.  I am convinced that the place of contact is the contact ring inside the column just below the steering wheel.  The same ring that the horn push is supposed to make contact with to sound the horn.  I notice on the Moto Lita wheel that I put on that there is a raised ridge of about 3/16 of an inch that is just above the contact ring.  I removed most of this but am still getting the horn to sound.  I next am looking at the likelihood that the ring is not staying seated in the column properly and is lifting up and that is making the contact.  There are some tabs that hold the ring in place. But over time those tabs appear to break off and then the ring is able to float around a bit.
I will let you know in a week or so when I get to that little problem, if I am successful in getting it to work properly.
Charley   

[Jim G]

Thanks Charley, my wheel is a Mota-Lita also, think it's called a Mark IV.
When I get a little more time I plan to look at it more carefully and I will let you know if I find anything also.
I swear I read a forum entry somewhere on the net about this same problem before I experienced it but cannot now find the article...

Jim

[charley fitch]

I took a quick look today at one of my TR4's that is NOT having a problem with the horn honking on its own.  I note that on this one I have a separation of the steering wheel from the column that is maybe 3/8 ".  I can see the horn contact ring  in the column and the base of the MotoLita wheel is maybe 3/16 to 1/4 inch above the contact ring.  This does two things, first it creates the separation of the steering wheel and the contact ring and second it gives me a little more distance of the steering wheel from the dash.  Yes, I am tall and really need the room for my knees.
I anticipate that I will try to duplicate this situation in the TR4 that is honking on its own.
Charley 

[Jim G]

Hi Charley - I've done a bit more investigation. Seems I may have a couple of different issues here. Although I have a voltage reading across the horn contact ring and the steering column, its not man enough to operate the horn. The "feed" for the ground seems to be coming through the steering column's outer flared top end rather than the column itself. This was making enough contact with the wheel's hub (by rubbing) to allow the horn to work when the horn push was pressed.
I *think* I may be missing the ground strap to the rack, I cant see it!
Where should that be?
Thanks.

Jim.

[charley fitch]

Hi Jim,
The grounding strap is a 6-8" braided wire that runs from the bolt on top of the steering rack (the one that you remove to put a grease zerk in to grease the rack) and I put the other end to the front bolt of the wheel suspension on the frame.  Any place on the frame is good as long as you have a good clean contact.  But you must remember that you also have two rubber bushings as a part of the steering shaft.  These bushings must also have wire ground straps to maintain the continuity of the ground all of the way up the steering shaft.  They make a special wire for these, but you can make up some yourself.  They are simply a heavier wire of about two inches in length with a loop at each end to accomodate a 1/4" bolt.  Use common sense to figure out how these go from one shaft to the other while going through the middle of the rubber piece.
I worked on my car recently and was able to separate the steering wheel from the column by another 1/8-1/4 ".  This appears to be what I needed to correct most of my problem. The other part of the problem was that the steering shaft was a bit loose and allowed the stering wheel to come down and make contact.  Problem solved--I HOPE.  Charley   

[Jim G]

Thanks Charley.
As a matter of fact, I chased continuity down the steering column from the horn contact slip ring and found that in addition to the missing rack ground, I am also missing the ground wire across the bottom column coupling (the top one is intact and working ok).
The Zerk nut you mention is the grease nipple thingy, right?
Also, I'm assuming to replace the lower coupling's ground wire, I need to remove the coupling, correct?
By the way I *think* the honking is due to the boss/hub actually touching the contact slip ring due to a very slight movement in the column. So when I turn right, I seem to be applying enough downwards pressure on the wheel to allow that movement. The slip ring is not in good shape, so I'm getting a new one in the hope that a less bashed up one might prevent that slightest of touching. We'll see...
Without the grounding up the column I cant move my wheel up a notch or 2 as you have done, altho that would fix the random honking, I'd have no earth connection at all to the hub then.

Jim

[charley fitch]

Hi,
First changing the continuity wire in the column coupling is easiest when it is out of the car.  But I would guess that getting the coupling out of the car is harder than trying to add/change the wire while the coupling is in the car.  I would try to add the wire while in the car first.  If that does not work then resort to removing the coupling.
Second the slip ring is held down in the column by three tabs that are a part of thecolumn outer shell. If these tabs are not being used or missing it may account for some movement of the ring. Next neither the column or shaft should be able to move.  If one or both are then I would look for where that movement is being allowed.  It can be from the coupling attachments or from the very upper part of the column.  I found mine to be in the very upper part of the column. Also the shaft is adjustable within the column and can be loose there as well.  To tighten up the upper part of the column and shaft, I removed the speedometer and tachometer.  This makes accessable the bolts at the firewall as well as the ones that are directly behind the dash face.  The other key item is the clamp that is on the shaft that is on the engine side of the firewall.  This allows the steering wheel to be adjusted up and down. I suggest you try to loosen this clamp and adjust your steering wheel/shaft up by maybe 1/4".  This  may very well give you enough distance to prevent the touching.  But I would also try to cure any looseness in the system.  This may sound hard to do, but it is really not.  Good luck,
Charley

[Jim G]

Charley - thanks for the feedback.
The tabs that hold the slip ring in place are actually in reasonable shape so I'm hoping if I'm gentle with them they'll stay intact...
Tell me, can you see any reason why the coupling ground wire should go through the middle of the coupling? I'm thinking as long as I keep the wire as short as possible and its not just left hanging out there, there's no reason why it can't go around the outside of the coupling. Keeping it tight so it doesn't snag anything.
Thoughts?

Jim.

[charley fitch]

Jim,
My only concern would be snagging something as you have noted.  This would be more of a concern on the upper coupling than the lower one.  One other item that I thought of.  The early TR4's had the solid steering rack mounts as opposed to the later ones that had the rubber mounts.  Therefore, the early cars do not really need the grounding wire as the later ones do.  But they all  need the wires at the  couplings.
Charley 

[Jim G]

Thanks again Charley and mine does have the rubber mounts.
Regards

Jim