Cadillac 2006 CTS-V Owner's Manual page 322

5. Draw or tape a horizontal line the width of the
vehicle at the wall or other flat surface where it
was marked it 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.
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.
Passenger's Side Shown
5-52
7. Locate the vertical headlamp aiming screws, which
are under the hood near each headlamp assembly.
The adjustment screw can be turned with a
6 mm hex socket.
8. Turn the vertical aiming screw until the headlamp
beam is aimed to the horizontal tape line. If you
turn it clockwise, it will raise the beam and if
you turn it counterclockwise, it will lower the beam.
The top edge of the cut-off should be positioned
at the bottom edge of the horizontal tape line.
9. Repeat Steps 7 and 8 for the opposite headlamp.