I spent years flailing around under the dash splicing and cobbling up wiring, but now I am old and patient, I print out an enlarged color copy of the wiring diagram and label as I go. I take photos of the wiring under the dash of what I think I might need to fix. I blow up the photos on the computer screen and try to match them with the Bentley. Then I fix the one circuit I planned to fix and make every minute of squeezing my 6’2 self under there count. Then I test it.
The steering lock pin grounds the horn contact as it goes from the outer shell of the column, and engages with the inner steering column shaft. This causes the horn to sound if there is something shorting out in the ignition switch, you are turning the switch without properly operating the steering lock or otherwise providing 12 volts to the fuse box while the steering is in locked position. It also makes the horn go off if you hot wire the battery to the coil. Normally as you turn on the ignition, the lock retracts the locking pin. If this doesnt happen, be very scared, as your steering may suddenly lock with the ignition on, as the pin finds the hole that it locks into. Put the horn back how it was and solve the problem and not the symptom !
Should the horn have a permanent live feed or ignition live? If I read your post correctly, the steering lock pin shorts the circuit instead of horn button being pressed. As it only happens when I take the key out and the steering lock pin touches the inner column but does not necessarily lock the steering then from what you are saying this is normal. It doesn’t do it whilst the key is turned or the ignition is on, so there is no danger of the pin locking with the key in the ignition. I have moved the horn power feed to ignition live only, so the horn doesn’t continually sound when the key is out of the ignition.
