the horn in rio r adjusable tone by turning the nut on top of the horn, however, if u turn too far, the horn wont sound. i'd tried 2 lower the tone of my horn since stock sound too funny to me, and i turn the nut a bit too loosen, so the horn sound worked sometime, but most of time i only get that relay clicking sound. so u may wana check out if the nut's loosen on the horn. and btw, since the horn suck so much dat i cant even hear my own horn when i have music on......i swap it into a pair of air horn