Klimfilt

Hi, guys i have a strange problem with my car. Yesterday i traveled 400km and in the middle of the road the horn started to honking, without pressing the wheel. I drove around 2km like that and it doesn't stop. So i stop the car, turned off the engine and after 5 min i starded again. And after 500 meters the problem showed again. I stoped and unhooked the horn cables under the hood, because it was a problem for other drivers at the road. When i arrived i hook it back and without turning on the engine the horn was honking again. (ignition switch on possition 2). Any ideas ? Yesterday it was hot ( 35 degrees) can it be from the temperature? May be the connectors are rusty?

EDIT: IT's not from the fuse, i've tried it now. First time when i put the key and pressed the wheel it was ok. When i presed it it's honking. When i don't i wasn't. After that i pull out the key, cleaned up the connectors and when i put the key, the problem it's showed again.