I have a 2001 Seville with 140,000 miles. I think the front end has sagged a bit over time. At night, my lowbeam headlights don't shine very far ahead. How do I adjust them? I see four star adjustment screws (two on either side) when I lift the hood.

 

Park the car so the headlights are 25 feet from a wall that is at least 6 feet high and 12 feet wide. Position the car square to the wall. The setup area needs to be flat and level from the wall to the tires. Close the doors, check the tire pressure, and have the fuel between 1/4 tank and full. Rock the car and let it find it's position.

Adjust the horizontal aim before the vertical aim.

Set horizontal aim to zero. Set the vertical aim to zero. This sets the aim dots so that measurements can be taken.

Measure the distance from the floor to the headlight aim dot. Mark a line on the wall at the same height. Mark a vertical line on the wall that is centered on the car by sighting thru the rear window and lining it over the hood.

Measure the distance between the headline aim dots and transfer them to the wall centered on the center line you previously established.

Mark offset spots on the wall 10.5 inches to the right and 5 inches down from these locations.

Turn the headlights on and aim them at these spots by adjusting the horizontal aim screw (on the side) first and the vertical aim screw (on the top) second.