From the fuse to the relay, how to pin down the cause of car horn loss
According to Mr. Tran Minh Tien - lecturer of Automotive Technology, Dung Quat College of Technology (Quang Ngai), when a car horn does not work, it is necessary to in turn check the components in the circuit to determine the exact cause.
First, the car owner can check the fuse and horn in the fuse box. The position and calibration of the fuse need to be determined based on the layout diagram of each car model. If the fuse is still good, the technician continues to check other parts in the circuit.
Next is the horn relay, if the car uses this type of relay. The position of the relay can be determined through the diagram on the fuselage box. With the common type of relay, the two power contact legs are responsible for turning on and off the horn supply; the remaining legs belong to the control circuit, receiving signals from the horn switch on the steering wheel or electrical module, depending on the structure of each car.
After removing the relay, the technician can check the power supply and closing and closing capability of the circuit based on the vehicle's electrical diagram. Measuring voltage at the relay legs helps determine the power supply, control line and contact point operation status, thereby cordoning off the cause of the horn loss.
Next, the horn cluster can be checked by supplying the power directly according to the correct voltage, electromagnetism and testing method specified by the manufacturer. If the horn emits normal sound when supplied with the correct power, the possibility of damage in the horn cluster itself can be further ruled out and other parts in the circuit can be checked.
Especially, on long-used vehicles, the torsion cable may be worn, damaged or the internal circuit breaks. At that time, the signal from the horn switch cannot be transmitted to the system. Depending on the vehicle configuration, the fault in the torsion cable can also affect some control buttons on the steering wheel or the airbag system, and also cause warning lights to appear.
Some other details to check
In addition, loose, oxidized, or broken jacks or wires can also disrupt the circuit. The problem with the cooling line of the horn cluster can also cause the horn to operate weakly or lose its sound, depending on the system design. Meanwhile, a weak battery can reduce the voltage supply, causing the horn to sound quiet or sound abnormal, but not all cases of horn loss originate from the battery.
If it is determined that the twisted cable or another part is damaged, the car owner should repair and replace it according to the correct cause. Checking before replacing components helps avoid unnecessary repairs.
The horn is a device that helps drivers send warning signals during traffic participation. Therefore, when the horn is not working, vehicle owners should check and fix it soon, instead of continuing to use the vehicle in a state where the sound warning system is disabled.
