Horn Won't work.

[nooberiffic]

The fuse blows the instant it is inserted. I figure there is a short somewhere. No power is getting to blue wire that goes into the two horns. Traced the wire back through the firewall. Checked at the horn relay under the dash by the coin tray. The relay works, and clicks when you hit the horn. However, no power is getting to that same blue wire as it runs into the relay. I checked one of the other two wires, and it has 12v. Any ideas?