ignition GMC SIERRA 2008 Service Manual

Puddle Lamps
If your vehicle has puddle lamps, they come on when
the unlock button on the Remote Keyless Entry
(RKE) Transmitter is pressed. The lamps time out or
turn off once the engine is started.
Fog Lamps
-(Fog Lamps):If your vehicle has fog lamps, the
control is located next to the exterior lamps control
on the instrument panel, to the left of the steering
column.
The ignition must be in the ON/RUN position for the fog
lamps to come on.
Press the button to turn the fog lamps on or off. A light
will come on in the instrument panel cluster.
When the fog lamps are turned on, the parking lamps
automatically turn on.
When the headlamps are changed to high-beam, the
fog lamps also go off. When the high-beam headlamps
are turned off, the fog lamps will come on again.
Some localities have laws that require the headlamps to
be on along with the fog lamps.
Auxiliary Roof Mounted Lamp
If your vehicle has this feature, this button includes
wiring provisions for a dealer or a qualied service
center to install an auxiliary roof lamp.
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 further information on roof mount emergency lamp
installation, please visit the GM Uptter website at
www.gmuptters.com or contact your dealer.
3-20

If your vehicle has this button, your vehicle may have
the snow plow prep package. For further information see
Adding a Snow Plow or Similar Equipment on
page 4-43.
Instrument Panel Brightness
D(Instrument Panel Brightness):This feature
controls the brightness of the instrument panel lights and
is located next to the exterior lamp 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.
Dome Lamps
The dome lamps come on when any door is opened.
They turn off after all the doors are closed.
The dome lamps can also be turned on by turning the
instrument panel brightness knob, located next to
the exterior lamps control, clockwise to the farthest
position. In this position, the dome lamps remain
on whether a door is opened or closed.
Dome Lamp Override
The dome lamp override button is located next to the
exterior lamps control.
k(Dome Off):Press the button in and the dome
lamps remain off when a door is opened. Press
the button again to return it to the extended position so
that the dome lamps come on when a door is opened.
Entry Lighting
Your 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.
3-21

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.
Normally, these actions occur in steps or levels, without
being noticeable. In rare cases at the highest levels
of corrective action, this action may be noticeable to the
driver. If so, a Driver Information Center (DIC)
message might be displayed, such as Battery Saver
Active or Service Battery Charging System. If this
message is displayed, it is recommended that the driver
reduce the electrical loads as much as possible. See
DIC Warnings and Messages on page 3-63.
Battery Run-Down Protection
This feature shuts off the dome and reading lamps, if
they are left on for more than 10 minutes after the
ignition is turned off. The cargo lamp shuts off
after 20 minutes. This prevents the battery from
running down.
Accessory Power Outlet(s)
Accessory power outlets can be used to connect
auxiliary electrical equipment, such as a cellular
telephone or CB radio.
The vehicle may have two accessory power outlets
located below the climate control system, or may have
one accessory power outlet and one cigarette lighter.
The cigarette lighter is designed to t only in the
receptacle closest to the driver.
There may be another accessory power outlet in the
rear cargo area. If the vehicle has a oor console, there
is an accessory power outlet inside the storage bin
and one on the rear of the oor console.
To use an accessory power outlet, remove the protective
cap. When not in use, always cover the accessory
power outlet with the protective cap.
Notice:Leaving electrical equipment plugged in for
an extended period of time while the vehicle is off
will drain the battery. Power is always supplied
to the outlets. Always unplug electrical equipment
when not in use and do not plug in equipment
that exceeds the maximum 20 ampere rating.
3-23

Certain power accessory plugs may not be compatible
to the accessory power outlet and could result in
blown vehicle or adapter fuses. If you experience a
problem, see your dealer/retailer for additional
information on the accessory power plugs.
The accessory power outlets are powered, even when
the ignition is in LOCK/OFF. Continuing to use
power outlets while the ignition is in LOCK/OFF may
cause the vehicle’s battery to run down.
Notice:Adding any electrical equipment to your
vehicle may damage it or keep other components
from working as they should. The repairs would not
be covered by your warranty. Do not use equipment
exceeding maximum amperage rating of 20
amperes. Check with your dealer/retailer before
adding electrical equipment.
When adding electrical equipment, be sure to follow the
proper installation instructions included with the
equipment.
Notice:Improper use of the power outlet can cause
damage not covered by your warranty. Do not
hang any type of accessory or accessory bracket
from the plug because the power outlets are
designed for accessory power plugs only.Ashtray(s) and Cigarette Lighter
Your vehicle may have a front ashtray located near the
center of the instrument panel. Pull on the door to
open it. The ashtray may have a cigarette lighter.
Notice:If you put papers, pins, or other ammable
items in the ashtray, hot cigarettes or other
smoking materials could ignite them and possibly
damage your vehicle. Never put ammable items in
the ashtray.
To remove the ashtray, open the door and pull the
ashtray bin toward you. To replace the ashtray, insert
the ashtray bin inside the ashtray door and press down
until it engages. To use the cigarette lighter, push it
in all the way, and let go. When it is ready for use, the
lighter pops back out.
Notice:Holding a cigarette lighter in while it is
heating does not let the lighter back away from the
heating element when it is hot. Damage from
overheating can occur to the lighter or heating
element, or a fuse could be blown. Do not hold a
cigarette lighter in while it is heating.
3-24

?(Recirculation):Press this button to turn the
recirculation mode on. When the button is pressed, an
indicator light will come on.
This mode keeps outside air from entering the vehicle.
It can be used to reduce outside air and prevent
odors from entering the vehicle. Recirculation may also
help cool the air inside the vehicle more quickly once
the temperature inside the vehicle is less than the
outside temperature.
The recirculation mode cannot be used with oor, defog
or defrost modes. If recirculation is selected with one
of these modes, the indicator light will ash three times
and then turn off. While in recirculation mode the
windows may fog when the weather is cold and damp.
To clear the fog, select either the defog or defrost
mode and increase the fan speed.
The recirculation mode can be turned off by pressing
the outside air button, or by turning off the ignition.
#(Air Conditioning):Press this button to turn the air
conditioning system on or off. When this button is
pressed, an indicator light on the button will come on to
let you know the air conditioning is activated. The air
conditioning can be selected in any mode as long as the
fan switch is on.
The air conditioning system removes moisture from the
air, so you may sometimes notice a small amount of
water dripping underneath your vehicle while idling
or after turning off the engine. This is normal.
Defogging and Defrosting
Fog or frost on the inside of windows is a result of high
humidity (moisture) condensing on the cool window
glass. This can be minimized if the climate control
system is used properly. To avoid fogging windows on
rainy and humid days at temperatures above freezing,
run the air conditioning compressor. It is best to
avoid the use of the recirculation mode, except when
maximum A/C performance is needed or for short times
to avoid exterior odors.
Turn the right knob to select the defog or defrost mode.
-(Defog):This mode clears the windows of fog or
moisture and warm the passengers. The air is directed to
the windshield, oor outlets, and side window vents.
0(Defrost):This mode removes fog or frost from the
windshield more quickly. A portion of the air is directed
to the windshield and the side window vents, with some
air directed to the oor vents. The system will
automatically force outside air into the vehicle.
The recirculation mode cannot be selected in the defog
or defrost mode. When either mode is selected, the
system runs the air conditioning compressor, unless the
outside temperature is close to freezing. Do not drive
the vehicle until all the windows are clear.
3-26

Rear Window Defogger
If your vehicle has a rear window defogger it uses a
warming grid to remove fog from the rear window.
The rear window defogger will only work when
the ignition is in RUN.
<(Rear):Press this button to turn the rear window
defogger on or off. An indicator light on the button
will come on to let you know that the rear window
defogger is activated.
The rear window defogger will only work when the
ignition is in RUN. The rear window defogger will stay
on for approximately 10 minutes after the button is
pressed, unless the ignition is turned to ACC or LOCK.
The defogger can also be turned off by pressing the
button again or by turning off the engine.
Notice:Do not use anything sharp on the inside of
the rear window. If you do, you could cut or
damage the warming grid, and the repairs would not
be covered by your warranty. Do not attach a
temporary vehicle license, tape, a decal or anything
similar to the defogger grid.
Climate Control System
(Heater Only)
With this system you can control the heating and
ventilation for your vehicle.
Operation
9
(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the fan speed.
Turn the knob all the way counterclockwise to turn the
front system off.
Temperature Control:Turn the center knob clockwise
or counterclockwise to increase or decrease the
temperature inside the vehicle.
3-27

)(Bi-Level):Air is directed partly to the instrument
panel outlets and to the oor outlets. A little air is
directed towards the windshield and side window outlets.
Cooler air is directed to the upper outlets and warmer
air to the oor outlets.
6(Floor):Air is directed to the oor outlets, with
some to the windshield, side window outlets, and
second row oor outlets. In this mode, the system will
automatically select outside air.
-(Defog):See “Defogging and Defrosting” later in
this section.
@(Recirculation):Press this button to turn the
recirculation mode on. When the button is pressed, an
indicator light comes on.
This mode keeps outside air from entering the vehicle.
It can be used to reduce outside air and prevent
odors from entering the vehicle. Recirculation may also
help cool the air inside the vehicle more quickly once
the temperature inside the vehicle is less than the
outside temperature.
The recirculation mode cannot be used with oor, defog,
or defrost modes. If recirculation is selected with one
of those modes, the indicator light ashes three
times and then turns off. The air conditioning
compressor also comes on when this mode is activated.While in recirculation mode the windows may fog when
the weather is cold and damp. To clear the fog,
select either the defog or defrost mode and increase the
fan speed.
The recirculation mode can be turned off by pressing
the outside air button, or by turning off the ignition.
;(Outside Air):Press this button to turn on
the outside air mode. When this mode is selected, air
from outside the vehicle circulates throughout the
vehicle. An indicator light on the button comes on to
show that it is activated. The outside air mode can be
used with all modes, but it cannot be used with the
recirculation mode.
Air Conditioning
#
(Air Conditioning):Press this button to turn the
air conditioning (A/C) compressor on and off. When
air conditioning is selected, an indicator light comes on
to show that the air conditioning has been activated.
Pressing this button when the outside temperature is too
cool for air conditioning makes the air conditioning
indicator ash three times and then turn off to let you
know the air conditioning mode is not available. If the air
conditioning is on and the outside temperature drops
below a temperature which is too cool for air conditioning
to be effective, the air conditioning light turns off to show
that the air conditioning mode has been canceled.
3-31

Speedometer and Odometer
Your speedometer lets you see your speed in both
miles per hour (mph) and kilometers per hour (km/h).
Your odometer shows how far your vehicle has
been driven, in either miles (used in the United States)
or kilometers (used in Canada).
Engine Hour Meter Display
The Driver Information Center (DIC) can also display
the number of hours the engine has run. To display the
engine hours, turn the ignition off, press and hold the
reset button for at least four seconds. The hour
meter will be displayed for up to 30 seconds, or until the
ignition is turned on. SeeDIC Operation and Displays
(With DIC Buttons) on page 3-55orDIC Operation
and Displays (Without DIC Buttons) on page 3-60for
more information.
Trip Odometer
The trip odometer can tell you how far your vehicle has
been driven since you last set the trip odometer to zero.
Press the reset button, located on the instrument panel
cluster next to the voltmeter, to toggle between the
trip odometer and the regular odometer. Holding
the reset button for approximately one second while the
trip odometer is displayed will reset it.
To display the odometer reading with the ignition off,
press the reset button.
SeeDIC Operation and Displays (With DIC Buttons) on
page 3-55orDIC Operation and Displays (Without
DIC Buttons) on page 3-60for more information.
Tachometer
Your tachometer displays the engine speed in
revolutions per minute (rpm). See “Grade Braking
(Allison Transmission
®)” underTow/Haul Mode on
page 2-34for more information.
3-36

Charging System Light
This light will come on
briey when you turn on
the ignition, but the engine
is not running, as a
check to show you it is
working.
It should go out once the engine is running. If it stays
on, or comes on while you are driving, you may have a
problem with the charging system. A charging system
Driver Information Center (DIC) message may also
appear. SeeDIC Warnings and Messages on page 3-63
for more information. This light could indicate that you
have problems with a generator drive belt, or another
electrical problem. Have it checked right away. If
you must drive a short distance with the light on, be
certain to turn off all your accessories, such as the radio
and air conditioner.
Voltmeter Gage
Your vehicle may have a
voltmeter gage.
When the ignition is on, this gage indicates the battery
voltage.
When the engine is running, this gage shows the
condition of the charging system. The gage may
transition from a higher to lower or a lower to higher
reading, this is normal. If the vehicle is operating outside
the normal operating range, the charging system light
will come on. SeeCharging System Light on page 3-43
for more information. The voltmeter gage may also
read lower when in fuel economy mode. This is normal.
3-43

Readings outside the normal operating range may also
occur when a large number of electrical accessories
are operating in the vehicle and the engine is left idling
for an extended period. This condition is normal
since the charging system is not able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself as higher engine
speeds allow the charging system to create maximum
power.
You can only drive for a short time with the readings
outside the normal operating range. If you must
drive, turn off all unnecessary accessories.
Readings outside the normal operating range indicate a
possible problem in the electrical system. Have the
vehicle serviced as soon as possible.Brake System Warning Light
With the ignition on, the brake system warning light
will come on when you set the parking brake. If you
try to drive with the parking brake engaged, a chime
will sound when the vehicle speed is greater
than 5 mph (8 km/h).
Your vehicle’s hydraulic brake system is divided into
two parts. If one part is not working, the other part can
still work and stop you. For good braking, though,
you need both parts working well.
If the warning light comes on and a chime sounds there
could be a brake problem. Have your brake system
inspected right away.
This light may also come on due to low brake uid. See
Brakes on page 5-42for more information.
United States
Canada
3-44