TR6 TR6 Horn only works when key is off

[wlivesey53]

I just bought this TR6 with 72000 miles on it, got it registered and now I need to get it inspected...among other things.
The car came with an after market steering wheel and now I have problems with its horn. Horn works when the engine is not running. Turn the key to first click and the horn doesn't work. Anyone run into this problem before??
Thanks in advance.
Bill L

 

[poolboy]

Do your headlights work when the key is in that position ?
AND since the electrical as well as other components have differences depending upon the model year of the car, you should include that information about your car's model year in your post.

 

[tomshobby]

Is it possibly connected to the power feed line for the anti run-on valve?

 

[TR3driver]

Check for the ground jumpers at the rubber coupling in the steering column and on the steering rack. I think it's grounding through the key buzzer switch or something like that.

 

[tomshobby]

Randall, the reason I was wondering about the anti run on wire is that it is hot when the ignition switch is off. It runs from the switch to the valve.

 

[TR3driver]

Randall, the reason I was wondering about the anti run on wire is that it is hot when the ignition switch is off. It runs from the switch to the valve.

Anything's possible, you may be right.

But the horn contact has to ground the wire to the horn relay and the jumpers sometimes get left disconnected (especially the one on the rack since you have to remove it to lube the rack). It's also an easy thing to check, so little time & effort wasted if I'm wrong.

 

[wlivesey]

Sorry for the delay but here is an update on my horn issue.
And per poolboy's suggestion I should specify the year of my TR6. It is a 1971.
In addition, it has an aftermarket 13"steering wheel which includes a non standard horn button. I could not find any identification of the steering wheel brand.
But here is the latest status: Now the horn only blows when I turn the steering wheel (either right or left) and I was able to test this while driving the car and when stopped with the key off. It will not blow when the steering wheel is not turning (ie, straight). I am thinking it has something to do with this steering wheel.
Any suggestions or insight is much appreciated.
Bill L

 

[Gliderman8]

Sounds like you are making "ground" when the wheel is turned thereby completing the horn circuit.
Check the brush inside the steering wheel.

 

[glemon]

My theory is that you have a bad ground or connection somewhere in the circuit that is barely capable of applying enough power to make the horn go beep, horns take a lot of juice, when you turn the key various things are competing with the horn for juice. Does it work with the car running, if so my theory may have some legs, as once started the volts should bump up a little as the alternator spins and does its work.

Theory number two, the horn circuit in the TR4-6 is the work of the devil, "abandon all hope ye who enter here" bribe the inspector and hope for the best.

 

[TR3driver]

A 71 TR6 should have a horn relay, which means the current through the horn button is minimal, roughly 1/10 amp.

If you can duplicate the problem sitting in the driveway, then it should be a simple task to add a temporary ground to the upper steering column and see if that makes it work. Of course it could be the contact inside the steering wheel/column, but grounding the shaft is easier than pulling the wheel off.
You can also try grounding the relay terminal with the purple/black wire and see if that makes the horn sound (it should). If it does, that narrows down the problem a bit.

 

[glemon]

As usual I stand corrected, assumed it was like my car, look like they added a relay in 1970. Its is still a kind of a crappy horn circuit design though.

 

[TR3driver]

Its is still a kind of a crappy horn circuit design though.

Just curious, what would you change? It's basically the same circuit used by every car I've ever owned (at least the ones with relays). My 95 Buick Roadmaster for example is exactly the same except it has two switches (one on each side of the air bag) instead of just one.

 

[glemon]

I probably could have omitted the word circuit by which I meant the means the electrons flow, and not how it looks on a wiring diagram. I have owned a TR4A and a TR250, both of which share the same horn design, which is carried over to the TR6 with the addition of the relays. Although I suppose 2 cars is not statistically significant, both have had chronic horn issues, the TR4A worked only when it wanted to, the TR250 more working when I don't want it to. The issues seem to revolve around the little tube with the spring and contacts in it in the wheel, the ground through the rubber u joints and wires in the steering column/shaft, and the proximity and ability for outer portions of the steering wheel mechanism to touch inner portions they are not supposed to creating horn when no horn is desired. Regards, Greg

 

[poolboy]

The only problem I've had with the horn has always been traced to dirty or carbonized contact surfaces on horn brush and the slip ring. I have to spray a solvent "in the vicinity" and turn the steering wheel back and forth half dozen times to clean them up.

 

[wlivesey]

Thanks for all the input guys. Here is what I have found:
The brush inside the after market steering wheel does seem to have been broken sometime by a previous owner. Although I don't know what a good brush looks like, it looks like the top of the plastic tube has broken off and the ~3/4" metal connector (brass?) is connected (taped) to the wire going to the horn button. So I will buy a new brush once I confirm the correct size - seems like there are 2 different lengths available (per Moss).
Also, it will blow but it is now very inconsistent when it does blow. The other day it would only blow when I was turning the wheel. Now there seems to be no consistency at all!
I did ground the button to the steering column and it did sound.
So first things first, I will order a new brush. I suspect it has something to do with the horn button connection that came with the after market steering wheel
Thanks again

 

[glemon]

Good luck!, sorry we took things astray, probably me more than anybody, but still discussion centered around how the steering wheel works (and doesn't).

 

[wlivesey]

Hmmm....this horn issue continues to challenge me. I am sure it is something "simple" but there seems to be no consistency when the horn will blow, or not blow. So here is the latest. I installed a new brush and changed the steering wheel boss. When I put a temporary ground on the steering wheel, or the upper steering wheel shaft, the horn would blow. When I went back to retest, the horn would not blow! Seems like there is no consistency, but I d believe it must be related to the ground. Your thoughts or suggestions would be appreciated.
BillL

 

[glemon]

Check the ground wire on the steering coupling and I believe there is one that goes from the column to the steering rack. Even if the wires look good check the contacts where the wires connect.

 

[DNK]

 

[wlivesey]

Thank you very much guys. I was able to sound the horn when I put a jumper wire across the lower and upper steering columns. I am assuming there is a bad connection at the coupling.
Thanks again for everyone's help. Now I need to get some loud horns so I can be heard. I once had Hella horns on another car, maybe that will be the solution.
Bill L