GMC 2009 Sierra 1500 Crew Cab Owner's Manual page 470

7. Locate the vertical headlamp aiming screws, which
are under the hood near each headlamp assembly.
The adjustment screw can be turned with
®
a 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.
5-60
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.