(1) Fault cause: ① The horn is damaged. ② The horn switch is damaged. ③ The connecting wire or connector is short circuited.

(2) Troubleshooting: ① After pressing the horn switch, use the multimeter voltage gear to detect the voltage at both ends of the horn wiring. If the voltage is normal, the horn is damaged. If there is no voltage, the horn switch is damaged or the wire is open circuited. Short circuit the two wires of the horn switch to quickly find the fault point. ② If the positive and negative poles of the electronic horn are connected inversely, the horn has no sound.