- Check for voltage at pin 30 with ignition on. If not there, then check fuse 7 and replace if burnt out.
- Check that pin 85 has 12V without the horn button being pressed and about 0V when horn button is pressed (with ignition on).
If pin 85 doesn't go to ground potential, then check the left hand controls connector for proper connections. Clean the contacts with cleaner like Deoxit.
- Check ground connections to frame for both the horns and horn button. Clean with a contact cleaner.
If after all this, no problem is found, the replace the relay.