horn!

i just got a 1989 jetta and the horn doesn't work.  the wires in the steering wheel seem to be hooked up but when i press down on the horn i just hear a clicking sound.  does anyone know if i need to replace the horn itself, or the horn relay???

any input would be great.  thanks!

lisa

   If you hear a click sound then the electrical and the
  relay is good, the horn is unpluged or bad