Sometimes the internet really isn’t the best of sources for car parts. A German vendor once fobbed right-hand drive headlights off on me on a web auction site. Sadly I only noticed when I checked the adjuster. Oncoming drivers would not have been amused, to paraphrase a famous queen in the land where asymmetrical light belongs on the left-hand side of the road. Apart from this rather rare reason, there are a number of others why headlights dazzle.
- Adjustment: An error which is easy to rectify but is far from being the only cause of glare. Workshops are the right place for adjusting your headlights, which can’t be done without the necessary equipment.
- Errors when replacing lamps: This problem is occurring more and more often. Strictly speaking, you should only be able to fit headlight lamps in one position in the headlights and lock them into place. Strictly speaking … but in practice errors can creep in quite easily. If too much force is applied, small detents which are supposed to prevent the lamp from being fitted incorrectly are easily broken off. Or spring clips are bent to such an extent that they lock the lamp into place at an angle. But if the lamp does not sit in the headlight in the exact position, the distribution of light will be heavily compromised, and adjusting the headlights won’t work any longer. Reading the lamp replacement instructions in the manual beforehand saves a lot of hassle and money which you may have to spend on a headlight which, in extreme cases, could be damaged.
- Low-quality lamps: A headlight is only as good as the light source in it. If the filament is not in exactly the correct position, the light will not be emitted as intended – too high, too low or in the wrong direction. And often the deviation can’t be rectified, not even by readjusting the headlights. Many no-name lamps have such large tolerances that this problem occurs quite often, whereas with brand lamps from Osram the tolerances are too narrow for the problem to occur.
- Broken headlights: Even the best of lamps won’t be able to work their magic if the headlight itself has flaws. This not only includes visible things such as cracked or worn headlight covers. Broken joints, routed-out setscrews, jammed adjusting motors – the number of causes increases with the complexity of modern headlights.
- Wrong headlight range: Headlamp leveling is one of the lesser known features on a car. This applies not only to models in which the xenon or LED lights are automatically kept at the right level as per regulations. Many drivers forget about the manual adjuster on the dashboard when driving with several passengers, heavy loads or even a trailer. Or they don’t even know what the adjuster is for. This quite often leads to the headlamp leveling system getting stuck after a few years. And by then the headlight range is probably all wrong too. You’ll find more information on its correct use in the manual. Among other things, it’ll tell you which setting is correct for which load. It’s quite rare that headlights have to be adjusted fully downwards. While they wouldn’t dazzle anymore, the headlight range would be pretty useless.