last night I noticed that the horn on my 4A worked when going straight ahead but did not work with the steering wheel at any other angle.
This morning I attacked the fault with my multimeter.
This showed that the fault was at the lower rubber UJ. As you know there is quite a lot of car in the way - mainly the alternator.
After a short struggle the alternator was out. Another test with the multiumeter showed that the fault was definitely there.
Rather than break the steering shaft down I decided to put a link around the outside of the UJ.
When finished I pressed the horn button and .............Nothing.
On closer inspection of the upper UJ I found that the electrical link was broken (I wish I had found this before taking the alternator out,)
I fitted another external link around the UJ - thankfully this now made a significant difference it now went .....toot.
How could the fairly large brass 1/4" ring connector break off. The UJ goes round but nothing else - how could it flex and break.