What Causes a Car Horn to Work Intermittently?
3 Answers
Car horn working intermittently may be caused by poor sealing, poor contact of the electromagnetic coil terminals, and contact point erosion. The following are detailed explanations: 1. Poor sealing leading to moisture: Although the horn is internally sealed, if the sealing is not tight, moisture may enter during car washing or water vapor may be present in the internal air space, which can easily cause the contacts to become damp and fail to function properly. 2. Poor contact of electromagnetic coil terminals: Some horns have aluminum metal rivet crimped connections for the enameled wire terminals of the internal electromagnetic coil. If the insulation paint on the enameled wire ends is not properly treated or the rivet crimping is not secure, it can lead to intermittent contact, causing the horn to malfunction. This issue is due to the horn's quality and cannot be repaired; it requires replacement. 3. Contact point erosion: Prolonged pressing of the horn can cause the contacts to erode, creating resistance. This reduces the electromagnetic attraction, preventing the armature from driving the diaphragm to vibrate normally, resulting in a hoarse sound or even no sound at all. However, when the horn is pressed continuously, a momentary strong current passing through the resistance may allow it to work intermittently, functioning sometimes and failing at other times.
I've been driving for most of my life and have encountered the issue of the horn working intermittently many times. The most common cause is the aging of the horn button on the steering wheel, where the internal copper contacts oxidize or wear out, leading to unstable connections when pressed. Another issue is the internal contacts of the horn itself becoming burnt or loose, which can worsen in humid weather. Aging wiring is also a culprit, such as corroded connectors or short circuits, especially during rainy days. Faulty relays causing unstable control or loose fuses before they blow can also lead to this problem. A simple first step is to clean the button and try pressing it with varying force. If that doesn’t work, check the fuse box to see if everything is intact. Safety-wise, a malfunctioning horn can be dangerous in emergencies, so don’t delay—schedule regular checks or visit a professional repair shop. It won’t cost much, but it could save your life.
As an amateur car repair enthusiast, I believe the intermittent horn failure issue mainly lies in component contact. Mechanical wear on the horn button increases contact resistance, causing no response when pressed lightly; loose or corroded copper plates inside the horn lead to performance degradation with weather changes. Short circuits or poor grounding caused by aging wiring, as well as oxidized relay contacts, can also result in intermittent operation. For DIY troubleshooting: check if the fuse is blown by pulling it out; press the horn to listen for the relay's clicking sound. Try cleaning the button contact surface or adjusting its position, but remember to disconnect the battery first to prevent short circuits. If DIY attempts fail, don't take risks—head straight to a repair shop for a comprehensive inspection. After all, the horn is crucial for emergencies during accidents, so it's not something to be careless about.
