What Causes the Car Horn Sound to Become Weaker?
3 Answers
The reason for a car horn's sound becoming weaker may include excessive battery discharge, burnt or poor contact points, loose or poor connections at the terminals, etc. Below is a detailed introduction to car horns: 1. Introduction: The horn is the audio signal device of a car. During driving, the driver uses it to emit necessary sound signals as required or regulated, to warn pedestrians and alert other vehicles, ensuring traffic safety. It is also used for urging movement and transmitting signals. 2. Working Principle: The car electric horn produces sound through the vibration of a metal diaphragm. It consists of an iron core, magnetic coil, contact points, armature, diaphragm, etc. When the driver presses the horn switch, current flows through the contact points to the coil, generating a magnetic force that pulls the armature down, forcing the diaphragm to move. The movement of the armature opens the contact points, interrupting the current and causing the magnetic force to disappear. The diaphragm, along with the armature, returns to its original position due to its own elasticity and the spring plate, closing the contact points again and restoring the circuit. Current flows through the contact points to the coil once more, generating magnetic force and repeating the above actions. This cycle continues, causing the diaphragm to vibrate repeatedly and produce sound.
As a veteran mechanic with ten years of experience, I can tell you that there are three most common issues when a car horn becomes quieter. Either the horn itself is faulty—the diaphragm gets rusted through by rainwater or the coil burns out, especially if the sound changes suddenly after rain, which usually indicates water ingress. Or there’s insufficient power supply—check if the 10A fuse in the fuse box has turned black, and then use a multimeter to measure the battery voltage. The trickiest issue is when the clock spring (spiral cable) in the steering wheel wears out and breaks the wires, which requires removing the steering wheel to inspect. I once helped a customer whose horn worked intermittently, and it turned out the spiral cable under the steering wheel had its insulation worn off. Troubleshooting isn’t too hard—first, try powering the horn directly to test the sound, then trace the wiring step by step.
Over the years of car modification, I've encountered the issue of horn volume reduction twice. The first time was due to voltage instability after installing xenon lights, which was resolved by adding capacitors. The second instance was more amusing - high-pressure car wash jets flushed insect carcasses into the horn grille, muffling the sound as if someone was covering its mouth. In daily use, the most common cause is metal diaphragm fatigue deformation, particularly for ride-hailing drivers who frequently use their horns - their vehicles often require horn replacements every two years. Also, a reminder for northern car owners: when spraying antifreeze in winter, avoid the horn area. Chemical corrosion of the metal diaphragm can make the tone sound particularly strange, resembling Donald Duck's voice.
