Porsche 2000 boxter horn blows constantly when fuse is - Fixya Apr 18, 2013Bought 2000 porsche boxter. Had it inspected, and passes. Later noticed the horn did not work. Was missing 25 amp fuse. Placed one in panel and horn would not stop blowing until fuse 2000 Porsche Boxster: fuse and now the horn works Apr 25, 2012I have a 2000 Porsche Boxster. The horn went out so I replaced the fuse and now the horn works. Trouble is that when I hit the brake while moving forward, the horn also blows. It doesn't happen when I brake while stationary or while in reverse.