How do you adjust headlamp aim on a citroen xantia?

To adjust the headlamp aim on a Citroën Xantia, first, park the vehicle on a level surface about 10-25 feet from a wall. Ensure the vehicle is loaded as it would be during normal use. Use a screwdriver to adjust the headlight vertical alignment screws, usually located on the back of the headlamp assembly, to achieve the correct beam height. Check the aim by turning on the headlights and ensuring the beam hits the wall at the appropriate height, typically around 2-3 inches below the horizontal centerline.