The horns on my car are not working- I thought that maybe I knocked something loose when I installed a new radio this summer, but I took off the lower panel on the drivers side and everything looks all right. I switched the horn relay in the front power distribution box with another one like it (same part #) and still no horn. The fuse is fine. Does anyone have any suggestions? Is there a common failure? I do not know when the horn stopped working, just that it used to work fine. I have a multi meter- how do I check that the horn relay is getting power, or that the switch is making contact? Any help is appreciated. TIA.