Horn not working can jump from battery and it works everything at the steering wheel seems intact and functional wondering about what I think is the relay a box mounted by the horn with wires going to the horn question is how do I test it and if bad where do I get one thanks for any help you can give me

 

found the relay replaced it and BEEP BEEP

 

I bought a new roadrunner horn and a relay. But the horn still don't work. I checked it with the battery and it works, but put it on the car and installed a new relay and it still won't work.
does anyone have any other ideas as to why it still doesn't work?