Cadillac 2012 CTS Owner's Manual page 347

The vehicle should:
Be placed so the headlamps
are 7.6 m (25 ft) from a light
colored wall.
Have all four tires on a level
surface which is level all the
way to the wall.
Be placed so it is perpendicular
to the wall.
Not have any snow, ice, or mud
on it.
Be fully assembled and have all
other work stopped while
headlamp aiming is being
performed.
Be loaded with a full tank of fuel
and one person or 75 kg
(160 lbs) sitting on the
driver seat.
Have all tires properly inflated.
Have the spare tire (if equipped)
in its original location in the
vehicle.
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:
1. Open the hood. See
for more information.
2. Locate the aim dot on the lens of
the low beam headlamp.
3. Record the distance from the
ground to the aim dot on the
low beam headlamp.