I had an issue with my horn, it turned out to be that the relay has gone bad. I swapped it with the adjacent relay, but it was just by trial and error diagnosis. I don't know what the adjacent relay is for, and have been unable to locate a schematic for this circuit, or with anything associated with the wiring that goes to the steering column. Does anyone have a clue, or a schematic.

I found a similar image of my relay harness, I've loaded it up, so that everyone can see what I'm talking about.