Brain Teaser

[todd reid]

More fun with Lucas Electrics!

I recently rewired my horns due to insulation breaking down on 48 year old wiring. New wire run from fuse block to horns and from horns to under dash connection with turn signal wiring harness.
Tested things in garage - OK. Drove car to work (48 miles) no issues. Upon starting car to drive home, horns sounded continuously as soon as steering wheel turned.

Unhooked wires, drove home. Was expecting a horn ring issue, but found no issue with it or any other part of system. Could not recreate problem in garage. Put it all together.

The next time I drove to work had the same problem. Ran fine all the way to work, horns sounded immediately upon start up on return trip.

I really can't come up with a plausible explanation for these events. Anybody have any theories?

Thanks in advance!

PS: Top put up when parking at work, windows left down - I don't believe any part of system is being subjected to extreme temperatures.

 

[Series6]

Thinking maybe your system bled the essential component when you opened your Lucas harness.

 

[Tom H]

I'm betting on a problem around the horn ring. And I'm suspecting it's temperature related. I forget exactly what experience I had regarding the horn ring, but it was a case where I had slightly misadjusted the three horn ring attaching screws ,or maybe I left out some washers. At any rate the horn was super touchy, and would beep at the slightest touch. I can imagine that a slight increase in temperature could have expanded something such that the horn would beep without touching it.

You say it sounded as soon as you started the car. Do you mean it sounded as soon as you turned the key to the ON position? Or did it require actually starting it each time?

Next time it happens, instead of pulling the wires, quickly undo the three screws holding the horn ring on and see what you find. You can anticipate and speed up the process by removing the center cover and the bolt that holds the steering wheel adjustment "knob". The knob will stay in place OK for a short trip .

Tom

 

[Bill Blue]

I have the same problem, only mine does not blow continuously. Just sometimes when the wheel is turned. I have had the dumb apart at least a dozen times, trying to find the problem. I'm pretty sure it is horn ring related and brought on by the contortions of the 50 year plastic covered steering wheel as it drys out.

While shims under the three screws seem to be a part of the answer, I found that shims under the steering wheel tightener helped, as did trimming the tightener so it no longer contacted the horn ring. Try backing the tightener off a turn, just to try to locate the problem. If all else fails, try increasing the contact ring gap a little.

After doing all this, my horn still occasionally beeps when turning the wheel when steering effort is high.

Bill

 

[Tom H]

I'm remembering a bit more, now. Like Bill, I found I had to insert washers behind the horn hub, on the 3 screws that hold the ring on. But I also remember it was no mystery. I could see that without those washers, the thin ring on the hub was very close to making contact with the copper ring on the column that is the ground. It also seems that this issue may have arisen after I repaired the horn ring by using JB Weld and some embedded nails to glue the ring back to the hub. And it was not the nails that was the issue, but somehow the thickness pf the JB Weld that created the problem.

Tom

Without disassembling mine, it's hard to remember precisely the issue, but next time you have the problem undo those 3 screws and you'll see that you are close to resolving it.

 

[todd reid]

Thanks to all for your input. I will report back when I find problem.

TR

 

[Hillman]

What Series? If SI, bad relay is possible.