Why is one headlight on while the other is off?
2 Answers
The reason for one headlight being on while the other is off could be due to a blown fuse, a short circuit in the bulb, or the bulb being burnt out. Below is an introduction to fuse-related content: 1. Replacement: If a car fuse is blown, the faulty fuse needs to be replaced. Besides getting it replaced at a repair shop, you can also replace the fuse yourself. Locate the fuse position based on the specific car model. Generally, the fuse box is near the battery. The fuse box usually has clips to secure it. 2. Current: When the current exceeds a certain limit for a period, the fuse will blow. If you replace it with a wire that doesn't blow easily, it may fail to prevent hazards properly, with the worst-case scenario being spontaneous combustion. Car fuses are inexpensive and easy to replace, and you can store extra fuses in the car's fuse tray.
One headlight is on while the other isn't—I've encountered this issue many times over decades of driving. Most likely, the bulb has burned out, especially during temperature fluctuations when filaments are prone to breaking. Simply replace it with a new bulb of the same model to avoid mistakes. The fuse could also be the culprit—open the fuse box, locate the one for the headlights, and replace it if blown. Loose or corroded wiring connections causing poor contact can interrupt the current; I once had this happen after water got into a connector during car washing. If the issue persists, check the relay or switch for faults. Safety first—uneven lighting at night makes it hard to see the road and increases accident risks. It's best to visit a repair shop promptly to test the alternator voltage, as excessive voltage accelerates bulb aging. Regular maintenance should include lighting checks to avoid roadside worries.
