Cadillac 2011 CTS Coupe Owner's Manual page 358

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.
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.
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, which are under
the hood near each headlamp
assembly. They are covered by
rubber caps.
The adjustment screw can be
turned with a 6 mm hex driver.
8. Turn the vertical aiming screw
until the headlamp beam is
aimed to the horizontal tape line.