2012 GMC SIERRA 1500 lights

Black plate (1,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Lighting 6-1
Lighting
Exterior Lighting
Exterior Lamp Controls . . . . . . . . 6-1
Exterior Lamps OffReminder . . . . . . . . . . . . . . . . . . . . 6-2
Headlamp High/Low-Beam Changer . . . . . . . . . . . . . . . . . . . . . 6-3
Flash-to-Pass . . . . . . . . . . . . . . . . . 6-3
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . 6-3
Automatic Headlamp System . . . . . . . . . . . . . . . . . . . . . . 6-4
Hazard Warning Flashers . . . . . 6-5
Turn and Lane-Change Signals . . . . . . . . . . . . . . . . . . . . . . 6-5
Fog Lamps . . . . . . . . . . . . . . . . . . . . 6-6
Auxiliary Roof-Mounted Lamp . . . . . . . . . 6-6
Interior Lighting
Instrument Panel IlluminationControl . . . . . . . . . . . . . . . . . . . . . . 6-7
Cargo Lamp . . . . . . . . . . . . . . . . . . 6-8
Dome Lamps . . . . . . . . . . . . . . . . . 6-8
Reading Lamps . . . . . . . . . . . . . . . 6-8
Lighting Features
Entry Lighting . . . . . . . . . . . . . . . . . 6-9
Exit Lighting . . . . . . . . . . . . . . . . . . . 6-9
Battery Load Management . . . . 6-9
Battery Power Protection . . . . 6-10
Exterior Lighting
Exterior Lamp Controls
The exterior lamps control is located
on the instrument panel to the left of
the steering wheel.
It controls the following systems:
.Headlamps
.Taillamps
.Parking Lamps
.License Plate Lamps
.Instrument Panel Lights
.Roof Marker Lamps
(If Equipped)

Black plate (2,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
6-2 Lighting
The exterior lamps control has
four positions:
O(Off):Turns off the automatic
headlamps and Daytime Running
Lamps (DRL). Turn the headlamp
control to the off position again to
turn the automatic headlamps or
DRL back on.
For vehicles first sold in Canada,
the off position will only work when
the vehicle is shifted into P (Park).
AUTO (Automatic): Automatically
turns on the headlamps at normal
brightness, together with the
following:
.Parking Lamps
.Instrument Panel Lights
.Taillamps
.License Plate Lamps
.Roof Marker Lamps
(If Equipped)
When the vehicle is turned off and
the headlamps are in AUTO, the
headlamps may automatically
remain on for a set time. The time of the delay can be changed using the
DIC. See
Driver Information Center
(DIC) on page 5‑30
;(Parking Lamps): Turns on the
parking lamps together with the
following:
.Instrument Panel Lights
.Taillamps
.License Plate Lamps
.Roof Marker Lamps
(If Equipped)
2(Headlamps): Turns on the
headlamps together with the
following:
.Parking Lamps
.Instrument Panel Lights
.Taillamps
.License Plate Lamps
.Roof Marker Lamps (If
Equipped)
When the headlamps are turned
on while the vehicle is on, the
headlamps turn off automatically 10 minutes after the ignition is
turned off. When the headlamps are
turned on while the vehicle is off,
the headlamps will stay on for
10 minutes before automatically
turning off to prevent the battery
from being drained. Turn the
headlamp control to off and then
back to the headlamp on position to
make the headlamps stay on for an
additional 10 minutes.
Push the turn signal/multifunction
lever toward the instrument panel to
change the headlamps from low
beam to high beam.
Exterior Lamps Off
Reminder
For vehicles with a radio, a reminder
chime sounds when the headlamps
or parking lamps are manually
turned on, the ignition is off, and a
door is open. To disable the chime,
turn the lamp off.

Black plate (3,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Lighting 6-3
Headlamp High/
Low-Beam Changer
5 3
(Headlamp High/Low
Beam Changer): To change the
headlamps from low to high beam,
push the lever toward the instrument
panel. To return to low-beam
headlamps, pull the multifunction
lever toward you. Then release it.
When the high beams are on, this
indicator light on the instrument
panel cluster will also be on.
Flash-to-Pass
This feature lets you use the
high-beam headlamps to signal
a driver in front of you that you want
to pass. It works even if the
headlamps are in the automatic
position. To use it, pull the turn signal lever
toward you, then release it.
If the headlamps are in the
automatic position or on low
beam, the high-beam headlamps
will turn on. They will stay on as
long as you hold the lever toward
you. The high-beam indicator on the
instrument panel cluster will come
on. Release the lever to return to
normal operation.
Daytime Running
Lamps (DRL)
Daytime Running Lamps (DRL) can
make it easier for others to see the
front of your vehicle during the day.
Fully functional daytime running
lamps are required on all vehicles
first sold in Canada.
The DRL system comes on when
the following conditions are met:
.The ignition is on.
.The exterior lamps control is
in AUTO.
.The transmission is not in Park.
.The light sensor determines it is
daytime.
When the DRL system is on,
only the DRL lamps are on. The
taillamps, sidemarker, instrument
panel lights, and other lamps will not
be on.
When it begins to get dark, the
automatic headlamp system
switches from DRL to the
headlamps.
To turn off the DRL lamps, turn the
exterior lamps control to the OFF
position and then release. For
vehicles first sold in Canada, the
transmission must be in the P (Park)
position before the DRL lamps can
be turned off.

Black plate (4,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
6-4 Lighting
Automatic Headlamp
System
When it is dark enough outside, the
automatic headlamp system turns
on the headlamps at the normal
brightness, along with the taillamps,
sidemarker, parking lamps, and the
instrument panel lights. The radio
lights will also be dim.
To turn off the automatic headlamp
system, turn the exterior lamps
switch to the off position and then
release it. For vehicles first sold in
Canada, the transmission must be
in the P (Park) position before the
automatic headlamp system can be
turned off.
The vehicle has a light sensor
located on the top of the instrument
panel which regulates when the
automatic headlamps turn on. Do
not cover the sensor, otherwise the
headlamps will come on whenever
the ignition is on.
The system may also turn on the
headlamps when driving through a
parking garage or heavy overcast
weather. This is normal.
There is a delay in the transition
between the daytime and nighttime
operation of the Daytime Running
Lamps (DRL) and the automatic
headlamp systems so that driving
under bridges or bright overhead
street lights does not affect the
system. The DRL and automaticheadlamp system are only affected
when the light sensor detects a
change in lighting lasting longer
than the delay.
If the vehicle is started in a dark
garage, the automatic headlamp
system comes on immediately.
Once the vehicle leaves the garage,
it takes approximately one minute
for the automatic headlamp system
to change to DRL if it is bright
enough outside. During that delay,
the instrument panel cluster may not
be as bright as usual. Make sure the
instrument panel brightness control
is in the full bright position. See
Instrument Panel Illumination
Control on page 6‑7.
To idle the vehicle with the
automatic headlamp system off,
turn the control to the off position.
The headlamps will also stay on
after you exit the vehicle. This
feature can be programmed using
the Driver Information Center (DIC).
See
Vehicle Personalization (With
DIC Buttons) on page 5‑48.

Black plate (7,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Lighting 6-7
This button is located on the
overhead console.
When the wiring is connected to
an auxiliary roof‐mounted lamp,
pressing the bottom of the button
will activate the lamp and illuminate
an indicator light at the bottom of
this button. Pressing the top of the
button will turn off the roof‐mounted
lamp and indicator.The emergency roof lamp circuit
is fused at 30 amps, so the total
current draw of the attached lamps
should be less than this value. The
attachment points for the roof lamp
circuits are two blunt cut wires
located above the overhead
console, a dark green switched
power wire and a black ground wire.
For more information on roof mount
emergency lamp installation, please
visit the GM Upfitter website at
www.gmupfitter.com or contact your
dealer.
If the vehicle has this button,
the vehicle may have the snow
plow prep package. For further
information, see
Adding a Snow
Plow or Similar Equipment on
page 9‑106.
Interior Lighting
Instrument Panel
Illumination Control
D(Instrument Panel
Brightness): This feature controls
the brightness of the instrument
panel lights and is located next to
the exterior lamps control.
Push the knob to extend out and
then it can be turned.
Turn the knob clockwise or
counterclockwise to brighten or dim
the instrument panel lights. Turning
the knob to the farthest clockwise
position turns on the dome lamps.

Black plate (9,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Lighting 6-9
Lighting Features
Entry Lighting
The vehicle has an illuminated entry
feature.
When the doors are opened, the
dome lamps will come on if the
dome override button is in the
extended position. If the dome
override button is pressed in, the
lamps will not come on.
Exit Lighting
The interior lamps come on when
the key is removed from the ignition.
They turn off automatically in
20 seconds. The lights do not come
on if the dome override button is
pressed in.
Battery Load
Management
The vehicle has Electric Power
Management (EPM) that estimates
the battery's temperature and state
of charge. It then adjusts the voltage
for best performance and extended
life of the battery.
When the battery's state of charge
is low, the voltage is raised slightly
to quickly bring the charge back up.
When the state of charge is high,
the voltage is lowered slightly to
prevent overcharging. If the vehicle
has a voltmeter gauge or a voltage
display on the Driver Information
Center (DIC), you may see the
voltage move up or down. This is
normal. If there is a problem, an
alert will be displayed.The battery can be discharged at
idle if the electrical loads are very
high. This is true for all vehicles.
This is because the generator
(alternator) may not be spinning fast
enough at idle to produce all of
the power needed for very high
electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, fog
lamps, rear window defogger,
climate control fan at high speed,
heated seats, engine cooling fans,
trailer loads, and loads plugged into
accessory power outlets.
EPM works to prevent excessive
discharge of the battery. It does this
by balancing the generator's output
and the vehicle's electrical needs.
It can increase engine idle speed to
generate more power whenever
needed. It can temporarily reduce
the power demands of some
accessories.

Black plate (27,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-27
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
does not work, then the vehicle
needs service.
Notice:Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer.
B (ACC/ACCESSORY): This
position lets things like the radio
and the windshield wipers operate
while the engine is off. Use this
position if the vehicle must be
pushed or towed.
C (ON/RUN): This position can
be used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. This position
can also be used for service and diagnostics, and to verify the
proper operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position on automatic transmission
vehicles.
If you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
D (START):
This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when
the driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.Starting the Engine
If the vehicle has a diesel engine,
see the Duramax® diesel
supplement for more information.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Notice: Do not try to shift to
P (Park) if the vehicle is moving.
If you do, you could damage the
transmission. Shift to P (Park)
only when the vehicle is stopped.
Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
Notice: If you add electrical parts
or accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See Add-On Electrical Equipment
on page 9‑105.

Black plate (45,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Driving and Operating 9-45
Shift the transfer case in one
continuous motion into or out of the
N (Neutral) position.
Electronic Transfer Case
The transfer case knob is located
next to the steering column.
Use the dial to shift into and out of
four-wheel drive.
Recommended Transfer Case Settings
Driving ConditionsTransfer Case Settings
2m 4m4n N
Normal YES Severe YES
Extreme YES
Vehicle in Tow* YES
*See Recreational Vehicle Towing on page 10‑93 orTowing the Vehicle on
page 10‑93.
You can choose among four driving
settings:
Indicator lights in the dial show
which setting you are in. The
indicator lights will come on briefly
when you turn on the ignition and
one will stay on. If the lights do not
come on, you should take the
vehicle to your dealer for service.
An indicator light flashes while
shifting the transfer case and
remains illuminated when the shift is complete. If for some reason the
transfer case cannot make a
requested shift, it will return to the
last chosen setting.
2
m(Two-Wheel Drive High):
This
setting is used for driving in most
street and highway situations.
The front axle is not engaged in
Two-Wheel Drive. This setting also
provides the best fuel economy.