Hey all I got a problem here with my 05 ralliart in which my horn wont stop activating at all unless I unplug the battery. I do have an aftermarket steering wheel and Hella horns in which I checked all the fuses, line and open the relay to find that theirs not problem. Any other ideas?

 

The way they're wired from the factory, the horn button grounds the control circuit of the relay, which trips the relay and sends battery power to the horns. If you are somehow grounding that circuit without pushing the horn button, your horns will sound continuously. First place I'd look is in the aftermarket steering wheel.