Common Trouble Shooting Of Car Horn:
1. If the horn is sometimes loud or sometimes not, the contact inside the horn switch is usually not good, and some are problems of the horn itself.
2. The scratchy sound is mostly due to the poor contact of plug, especially each contact around the steering wheel, which is easily worn due to frequent use.
3. No noise at all. First, check the fuse to see if it fuses, then pull the horn plug, and use a multimeter to measure whether there is electricity when the horn switch is pressed. If there is no electricity, check the horn harness and relay. If there is electricity, it is a problem of the horn itself. At this time, you can also try to adjust the adjusting nut on the horn to see if it can sound. If it still doesn't sound, you need to replace the horn.