Horn stuck on, and it's not the steering column
 

1987 Jaguar XJ12 Vanden Plas Canadian beast. Horn should function by grounding the green wire of the relay via the horn push, connecting the horn to power. Horn wires were detached, so I reinstalled. Relay was missing, put in a known good one. Fuse was blown behind battery, put in a new one. Now the horn is so happy it won't stop. Pull the under-dash fuse and the horn will stop. On the steering column, there's a little black wire which should connect the column to ground, and pulling that should be as good as pulling the fuse, right?? Pulling it doesn't stop the honking. I'm basically trying to track down where this horn is getting a permanent ground and I'm not finding it.


-John


(btw I'm not that new, but I couldn't get my old name working)

on my 86 xj6 the problem was the spring that makes the contact on the column at the bottom had come adrift and wound itself around the inside giving me the same result as yours

this was exactly my problem as well - I had trouble diagnosing it because after pulling fuse, adjusting, and reinserting fuse it would stop but then it seemed to get more frequent or to start up again after the front of the car would get wet (washing, heavy rain, etc)

Thank you for the replies. I'm certain you are correct about the spring. Adjusted the steering column out and the problem is gone :)