I have a 2000 Porsche Carrera 911 (996 Model) and my horn sometimes goes off for no reason, when I go over a speedbump it goes off. I also had my car alarm or my horn (I am not sure because I was not at my car) goes off every 1/2 hour all day until my battery went dead. My neighbor told me if was going off for no reason. Anyone know what it might be?

 

Ah, ok. There are horn bushings on a plate behind the horn assembly. They get soft and need to be replaced. IIRC there are 4 small rubber bushings.