GMC 2011 Sierra - Manual (Page 466)

Black plate (42,1) GMC Sierra Owner Manual - 2011
10-42 Vehicle Care
Headlamp Aiming
The vehicle has a visual optical
headlamp aiming system. The aim
of the headlamps has been preset
at the factory and should need no
further adjustment.
However, if the vehicle is damaged
in a crash, the aim of the headlamps
may be affected and adjustment
may be necessary.
If oncoming vehicles flash their high
beams at you, this may mean the
vertical aim of the headlamps needs
to be adjusted.
It is recommended that the vehicle
be taken to the dealer for service if
the headlamps need to be adjusted.
It is possible, however, to re-aim the
headlamps as described.
The vehicle should:
. Be placed so the headlamps
are 7.6 m (25 ft) from a
light‐colored wall.
. Have all four tires on a level
surface which is level all the
way to the wall.
. Be placed so it is perpendicular
to the wall.
. Not have any snow, ice, or mud
on it.
. Be fully assembled and all other
work stopped while headlamp
aiming is being performed.
. Be loaded with a full tank of
fuel and one person or 75 kg
(160 lbs) sitting on the
driver seat.
. Have the tires properly inflated.
. Have the spare tire in its proper
location in the vehicle.
Headlamp aiming is done with the
vehicle's low-beam headlamps.
The high-beam headlamps will be
correctly aimed if the low-beam
headlamps are aimed properly.
To adjust the vertical aim:
1. Open the hood. See Hood on
page 10‑5.
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.