I've been searching the engine bay and crawling around under the front of my xB trying to locate the horn to see how much of a pain it would be to swap it out for something with more *****. I didn't see anything that was obviously the horn, but there's an unidentifiable metal blob low on the driver side. Am I warm? :?:

 

the horn is up front and high... If you've done the "clear" job to your headlights then you've seen them. I replaced mine, while I already had the bumper off for the lights.

 

OK, I found it. On the driver side, behind the upper honeycomb grille. The sun had shifted enough for me see it.