What causes a car horn to keep sounding continuously?
2 Answers
The reason a car horn keeps sounding continuously may be due to the power wire of the horn being constantly energized. This constant power supply could be caused by the horn button on the steering wheel being stuck in the engaged position or the relay contacts failing to disconnect properly and remaining closed. Below is an analysis of potential reasons why a car horn may not stop sounding: 1. Contact Point Erosion: Prolonged pressing of the horn can cause the contacts to erode, creating resistance. This reduces the current flow through the electromagnetic coil, diminishing the electromagnetic force and preventing it from attracting the armature to drive the diaphragm's normal vibration, resulting in a hoarse sound or no sound at all. 2. Poor Sealing Leading to Moisture: Although the interior of the horn is supposed to be sealed, if the sealing is not tight, moisture can enter during car washing or water vapor can accumulate inside. This moisture can cause the contacts to become damp and malfunction, leading to poor connection at the electromagnetic coil terminals and resulting in no sound.
Hey, as someone who often tinkers with cars, I think if the horn keeps sounding, it's mostly due to a stuck button or switch, especially in older cars where aging plastic parts can easily get jammed and fail to pop back up. It could also be a short circuit in the wiring, like moisture corrosion or rodents chewing through the wires, allowing current to flow directly to the horn. Relay failure is also common—that thing controls the current, and if it burns out or the contacts stick together, the horn will keep blaring. Fuse issues are less common but can sometimes cause loss of control if they blow. Voltage instability can also cause trouble, like an alternator outputting too high a voltage, making the control unit malfunction. If this happens on the highway, it's too noisy and distracting—pull over immediately and temporarily fix it by pulling the horn fuse. For safety, I suggest not toughing it out; head straight to the repair shop and let a mechanic check it with a multimeter to avoid draining the battery or worse.
