Cadillac 2012 CTS Owner's Manual page 348

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.
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.
9. Make sure that the light from the
headlamp is positioned at the
bottom edge of the horizontal
tape line. The lamp on the
left (A) shows the correct
headlamp aim. The lamp on the
right (B) shows the incorrect
headlamp aim.
10. Repeat Steps 7 through 9 for
the opposite headlamp.