2010 Cadillac DTS Owner's Manual - Page 362

4. At a wall, measure from the ground upward (A) to the recorded distance from Step 3 and mark it. 5. Draw or tape a horizontal line (B) the width of the vehicle at the wall where it was marked in Step 4. Notice: Do not cover a headlamp to improve beam cut-off when aiming. Covering a headlamp may cause excessive heat build-up which may cause damage to the headlamp. 6. Turn on the low-beam headlamps and place a piece of cardboard or equivalent in front of the headlamp not being aimed. This should allow only the beam of light from the headlamp being aimed to be seen on the flat surface. 7. Locate the vertical headlamp aiming screws. They are located under the hood near each headlamp assembly. First lift the flap to access either of them. Each one is the top outboard screw by the " V" on the cover panel next to the aiming flap. The adjustment screw can be turned with a 6 mm hex wrench. 8. Turn the vertical aiming screw until the headlamp beam is aimed to the horizontal tape line. Turn it clockwise or counterclockwise to raise or lower the angle of the beam. The top edge of the cut-off should be positioned at the bottom edge of the horizontal tape line. 6-42