2008 GMC SIERRA open hood

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 ash their high beams at you, this
may mean the vertical aim of your headlamps needs
to be adjusted.
It is recommended that the vehicle is taken to your
dealer/retailer 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 25 ft. (7.6 m) 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.
Normally loaded with a full tank of fuel and one
person or 160 lbs (75 kg) sitting on the driver seat.
Have the tires properly inated.
Have the spare tire is 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. SeeHood Release on page 5-13
for more information.
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.
5-57

Headlamps
To replace one of these bulbs:
1. Open the hood. SeeHood Release on page 5-13
for more information.
2. If you are replacing the bulb on the passenger side
remove the Engine Air Cleaner cover. SeeEngine
Air Cleaner/Filter (Gasoline Engines) on page 5-19
for more information.
3. Reach in and access the bulb sockets from inside
the engine compartment.
4. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly and pull it straight out.
5. Unplug the electrical connector from the old bulb by
releasing the clips on the bulb socket.
6. Replace it with a new bulb socket.
7. Plug in the electrical connector to the new
bulb socket.
8. Reinstall the new bulb socket into the headlamp
assembly and turn it clockwise to secure.
9. Close the hood.
5-60

Fuel (cont.)
Fuels in Foreign Countries.............................. 5-9
Gage.........................................................3-53
Gasoline Octane........................................... 5-6
Gasoline Specications.................................. 5-6
Low Warning Light.......................................3-54
Fuses
Center Instrument Panel Fuse Block.............5-125
Fuses and Circuit Breakers.........................5-123
Instrument Panel Fuse Block.......................5-124
Underhood Fuse Block...............................5-126
Windshield Wiper.......................................5-123
G
Gage
Engine Coolant Temperature.........................3-46
Fuel..........................................................3-53
Oil Pressure...............................................3-50
Speedometer..............................................3-36
Tachometer.................................................3-36
Voltmeter Gage...........................................3-43
Garage Door Opener.......................................2-68
Gasoline
Octane........................................................ 5-6
Specications............................................... 5-6
Glove Box.....................................................2-74
GM Mobility Reimbursement Program.................. 7-6
H
Hazard Warning Flashers................................... 3-8
Head Restraints..............................................1-10
Headlamp
Aiming.......................................................5-56
Headlamps....................................................5-60
Bulb Replacement.......................................5-59
Daytime Running Lamps...............................3-18
Exterior Lamps............................................3-17
Flash-to-Pass..............................................3-11
Halogen Bulbs............................................5-59
High/Low Beam Changer..............................3-11
On Reminder..............................................3-18
Pickup Box Identication and Fender
Marker Lamps.........................................5-62
Heated Seats................................................... 1-6
Heater...................................................3-25, 3-27
Heater...........................................................3-28
Highbeam On Light.........................................3-52
Highway Hypnosis...........................................4-29
Hill and Mountain Roads..................................4-30
Hood
Checking Things Under................................5-12
Release.....................................................5-13
Horn............................................................... 3-8
How to Wear Safety Belts Properly...................1-19
6