Buick 2010 Lacrosse Owner's Manual page 315

The vehicle should be placed so
it is perpendicular to the wall or
other flat surface.
The vehicle should not have any
snow, ice, or mud on it.
The vehicle should be fully
assembled and all other work
stopped while headlamp aiming
is being performed.
The vehicle should be normally
loaded with a full tank of fuel and
one person or 75 kg (160 lbs)
sitting in the driver's seat.
Tires should be properly inflated.
Headlamp aiming is done with the
vehicle's low-beam headlamps. The
high-beam headlamps will be
correctly aimed if the low-beam
headlamps are aimed properly.
To adjust the vertical aim, do the
following:
1. Open the hood. See
2. Locate the aim dot on the lens of
the low beam headlamp.
3. Measure the distance from the
ground to the aim dot on the
low beam headlamp. Record the
distance.