2010 Buick LaCrosse Owner's Manual - Page 313

Vehicle Care 5. Draw or tape a horizontal line (B) on the wall the width of the vehicle at the height of the mark 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. 4. At the wall measure from the ground upward (A) to the recorded distance from Step 3 and mark it. 6. Turn on the low-beam headlamps and place a piece of cardboard or equivalent in front of the headlamp not being adjusted. This allows only the beam of light from the headlamp being adjusted to be seen on the flat surface. Base 9-33