GMC 2011 Sierra - Manual (Page 467)

Black plate (43,1) GMC Sierra Owner Manual - 2011
Vehicle Care 10-43
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)
on the wall the width of the
vehicle at the height of the
mark in 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 adjusted. This allows
only the beam of light from the
headlamp being adjusted to be
seen on the flat surface.
7. Locate the vertical headlamp
aiming screws, which are under
the hood near each headlamp
assembly.
The adjustment screw can be
turned with an E8 Torx
® socket.
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.