What is the reason when the low beam headlights appear to be on but seem ineffective?
2 Answers
This may be due to the height adjustment of the low beam headlights, which can be adjusted at a 4S shop. Alternatively, it could be caused by window tinting films with poor light transmittance, leading to this situation. Here is some information about car lights: Low beam headlights: Designed for close-range illumination, they feature a wide coverage angle (160°) but a short projection distance, and the focus cannot be adjusted. Function: Low beam headlights have a distinct cutoff line between light and dark. Most vehicle low beams illuminate a distance of 30-40 meters, with the cutoff line located around 12-18 meters. The area in front of the cutoff line is brightly lit, allowing clear object identification, and a visibly illuminated area of 2-3 meters in diameter can be seen on the ground. The area from the cutoff line to 30-40 meters relies mainly on ground-reflected light, where brightly colored objects can still be distinguished. High beam headlights: These should only be used when there are no other lighting facilities on the road and no oncoming vehicles, as they can severely impair the vision of other drivers.
Sometimes my car does the same thing, the low beams are on but it feels like they're not. This is usually a burnt-out bulb, the most common issue, especially if it hasn't been changed for several years—the filament breaks and it won't light up. Another reason could be a blown fuse; you might find the corresponding one burnt out in the fuse box, and replacing it should fix the problem. Poor wiring connections are also common, like loose plugs or aged wiring, which prevent current from passing through. There could also be a faulty switch or relay, where the headlight igniter is broken and the signal doesn't reach the bulb. I recommend starting with simple checks: pop the hood and inspect the bulb's condition, then take a look at the fuse box—make sure to mark them clearly to avoid confusion. If that doesn't solve it, it's best not to tinker blindly and instead head straight to a repair shop for professional diagnosis. Driving at night with poor lighting is dangerous as it affects visibility. Regularly replacing bulbs can prevent this issue—check them about every two years.
