There are several reasons your system isn't working. The horn and the compressor are on the same fuse, so if the horn doesn't work, check the fuse. That's the easy one.
Unfortunately, the OEM compressor is cheap crap. Lots of them have been replaced. At the present time I am one of the victims. My compressor was making a lot of noise and now the compressor motor runs, but it doesn't pump air. I'm going to replace it with a Viair compressor. Here is an excellent write up on how to do it by NoJive,
http://www.spyderlovers.com/forums/s...ith-Viair-097c
Also, you should check to see if the system holds air. Use a tire gauge on the schrader valve located under the seat. Make sure you don't add more than 80psi if you do add air.