I found this thread while troubleshooting my non-working horn issue. Had a good fuse and relay so replaced the clock spring however that did not resolve the issue. After checking the relay cavities I realized there was no voltage at cavity 86. After pulling the junction box and removing the back cover I found it wet and corroded. Found out that water was getting in through the hole for the radio antenna in the wheel well. Seeing how there was no wheel well liner it must have been kicking up enough water to soak it regularly. New junction box on eBay for $40 and now I have a working horn.