156 Horn wasn't working (it is now)
The horn stopped working on my 2002 156 GTA. I did all the obvious things like check the fuses and then I searched on here. After reading several threads I decided to disconnect the battery, wait 30 minutes and then remove the centre of the steering wheel. For anyone considering the same it's a 5mm Allen key to undo the bolts, not a Torx (well at least it was on mine). Nothing under there looked adjustable so I bent the contacts a bit with pliers, put it all back together but it still didn't work. Had a second go, figuring I'd disconnect the Airbag completely, then reconnect the battery and have a better idea of what was going on. I could not get the Airbag disconnected, no way was I going to play with the strange looking connector on the back of the airbag itself, and the wiring wasn't unplugable from the other end. So, I put it all back together a second time. It still didn't work.
Time to call in the professionals. A mobile auto electrician arrived and the first thing he did was remove the plastic cowling from above and below the steering column, which is 5 screws and alot easier than removing the centre of the steering wheel - doesn't need the battery to be disconnected either. Looking to identify the wires, moved a couple, pressed the horn, and hey presto, it worked. Put everything back together, it still worked. 2 weeks and several hundred miles later, it still works.
Just thought I'd post this in case anyone else has a similar issue.