Good lighting matters for night driving. If your headlights are dim, flicker or keep blowing bulbs, there is usually an electrical cause that can be found.
Possible causes
- Weak charging. A tired battery or alternator cannot keep voltage steady, so lights dim at idle.
- Poor earth connection. A corroded ground strap can make lights flicker or look yellow.
- Failing bulbs or ageing lenses. Halogen bulbs fade over time, and cloudy plastic lenses cut the light output.
- Loose connectors. Heat and vibration can loosen the plug behind the headlight.
- Blown fuse or faulty relay. One light out or both going off together points this way.
Bulbs that keep blowing
Repeated bulb failure often means too high a voltage from the charging system, moisture inside the housing, or the wrong bulb type. Swapping the bulb again will not fix it.
Check before you drive at night
Walk around the car with the lights on and look at the beam on a wall. Both sides should be bright and even. If they are not, get the wiring and charging checked rather than driving with poor visibility.