Suddenly, last friday, my horns stopped working. I chased every possible ghost, and no luck. On a strike of pure luck, looking under the dash, I spotted a small switch someone instaled. Gave it a try on all three positions and it was a kill switch for the horns.
It seems that over the time, somewhere, it had more than two and the switch made them work. Intermediate position killed everything, and inadvertedly I touched it while driving looking for the source of a clanking sound the car was making.
So.. look under the dash just in case.
So...