Drivers tend to confuse this little wheel and knob, thinking that the control for headlight leveling is the dimmer for the instrument lights. The fact that the two are very close together on the light switch and the symbols are not particularly helpful contribute to this confusion. On top of that, many drivers don’t even know headlight leveling exists or how to use it. And if they do, they only know two positions for the control: off and maximum. In the latter case, they throw away valuable visibility in most cases. There are two groups that don’t need to worry about headlight leveling. Firstly, owners of cars with xenon lights or almost all LED headlights. Here, the headlight range is regulated automatically. And secondly, drivers in the USA don’t have to bother with all this. Their vehicles don’t have headlight leveling.
What does headlight leveling do?
It’s important to know that it doesn’t extend the headlight range or visibility. It can only reduce them if the rear of the car is pushed down and the headlights therefore shine upward, dazzling other drivers.
How do the headlights control it?
Today it’s usually an electric motor which moves the reflector and adjusts the height. In projection systems, in other words lens headlights, the inclination of the whole luminaire unit is adjusted in the headlight. Early systems had no electric drive but relied on pneumatics or hydraulics. Both were often faulty and are therefore now extinct.
When is headlight leveling used?
Always when the rear is pushed down by the load in the trunk. If the car is occupied with several people, especially heavy ones, the effect is the same. Now, the impact in an SUV weighing several tonnes will be lower than in a small car. In one case, adjusting the headlight range may not be necessary at all or only by one step, while another case calls for maximum leveling. Driving with a trailer almost always requires an adjustment.
How much does the control need to be adjusted?
As already mentioned, this very much depends on the vehicle and the load. The manual will shed light on it so it’s worth having a look. Making no adjustments is just as bad an idea as always turning the wheel as far as the end position. The latter can reduce the range of the headlights considerably.
What else do you need to keep in mind?
Turn it back! Once you have unloaded the trunk or the driver is in the car alone again, it’s time to reset the wheel to zero. It’s also worth taking a look at the control after cleaning the dashboard. When you wipe over it, the little wheel may get turned by accident. That applies both to headlight leveling and the brightness adjuster for the instruments. Don’t confuse these two!