Your horn does not work on your 2003 c240 Mercedes Benz what do you do?

If the fuse for the horn is blown, the horn will not work. If you replace the fuse and it blows again, there is a problem with circuit or the horn is bad and needs to be replaced. You can try removing the horn and cleaning it, then connecting it directly to the battery to see if it works. If you're not experienced with this, have a mechanic check it. It is also possible the connection is corroded, or a wire is loose or broken.