wiring GMC SIERRA CLASSIC 2007 Owners Manual

Q:What if I added a snow plow? Will it keep
the airbags from working properly?
A:We have designed our airbag systems to work
properly under a wide range of conditions,
including snow plowing with vehicles that have
the optional Snow Plow Prep Package
(RPO VYU). But do not change or defeat the
snow plow’s “tripping mechanism.” If you
do, it can damage your snow plow and your
vehicle, and it may cause an airbag ination.
Q:Because I have a disability, I have to get
my vehicle modied. How can I nd out
whether this will affect my advanced airbag
system?
A:Changing or moving any parts of the front
seats, safety belts, the airbag sensing and
diagnostic module, steering wheel, instrument
panel, the inside review mirror, or airbag
wiring can affect the operation of the airbag
system. If you have questions, call Customer
Assistance. The phone numbers and
addresses for Customer Assistance are in
Step Two of the Customer Satisfaction
Procedure in this manual. SeeCustomer
Satisfaction Procedure on page 638.
110

The headlamp control has four positions:
9(Off):Turn the control to this position to turn
off the Daytime Running Lamps (DRL) and
the automatic headlamps.
AUTO (Automatic):Turn the control to this
position to activate the automatic headlamp mode.
;(Parking Lamps):Turn the control to this
position to turn on the parking lamps, together with
the following:
Sidemarker Lamps
Taillamps
License Plate Lamps
Instrument Panel Lights
Roof Marker Lamps (If the vehicle has them)
5(Headlamps):Turn the control to this position
to turn on the headlamps, together with the
previously listed lamps and lights.Switch the headlamps from high to low-beam by
pushing the turn signal/high-beam lever towards
the instrument panel.
A circuit breaker protects the headlamps. If you
have an electrical overload, the headlamps
will icker on and off. Have your headlamp wiring
checked right away if this happens.
Headlamps on Reminder
A reminder chime will sound when the headlamps
or parking lamps are manually turned on and
your ignition is off and a door is open. To disable
the chime, turn the light off.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier
for others to see the front of your vehicle during
the day. DRL can be helpful in many different
driving conditions, but they can be especially
helpful in the short periods after dawn and before
sunset. Fully functional DRL are required on all
vehicles rst sold in Canada.
222

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 center of the
instrument panel near
the climate controls.
When the wiring is connected to an auxiliary roof
mounted lamp, pressing the button will activate
the lamp and illuminate an indicator light near the
button. Pressing the button again will turn off
the roof mounted lamp.
If your vehicle has this button, your vehicle may
have the snow plow prep package. For further
information seeAdding a Snow Plow or Similar
Equipment on page 416.
Instrument Panel Brightness
D(Instrument Panel Brightness):This feature
controls the brightness of the instrument panel
lights.
The thumbwheel for this feature is located next to
the headlamp control.
Move the thumbwheel up to adjust the instrument
panel lights and to return the radio display to
full brightness when the headlamps or parking
lamps are on. To turn on the dome lamps, move
the thumbwheel to the farthest position.
Dome Lamps
The dome lamps come on when a door is opened.
The dome lamps can be turned on by moving
the thumbwheel, located next to the exterior lamps
control, to the farthest position. In this position,
the dome lamps will remain on whether a door is
opened or closed.
226

Safety Belt Reminder Light
When the key is turned to RUN or START, a
chime will sound for several seconds to remind
people to buckle their safety belts. The driver
safety belt light will also come on and stay on for
several seconds, then it will ash for several
more. You should buckle your seat belt.
This chime and light will
be repeated if the driver
remains unbuckled
and the vehicle
is in motion.
SeeDIC Warnings and Messages on page 270for
more information on driver and passenger
safety belt reminders.
If the driver’s belt is buckled, neither the chime nor
the light will come on.
SeePassenger Sensing System on page 103for
more information.
Airbag Readiness Light
There is an airbag readiness light on the instrument
panel cluster, which shows the airbag symbol. The
system checks the airbag’s electrical system for
malfunctions. The light tells you if there is an
electrical problem. The system check includes the
airbag sensors, the airbag modules, the wiring and
the crash sensing and diagnostic module and, if
equipped, the passenger sensing system. For more
information on the airbag system, seeAirbag
System on page 91.
This light will come on
when you start your
vehicle, and it will ash
for a few seconds.
This means the system
is ready.
If the airbag readiness light stays on after the
vehicle is started or comes on while you are
driving, the airbag system may not be working
properly. Have your vehicle serviced right away.
247

Q:What is total vehicle reserve capacity?
A:This is the difference between your GVWR and
the weight of your truck with full fuel and
passengers. It is the amount of weight you can
add to your vehicle before reaching your
GVWR. Keep in mind that reserve capacity
numbers are intended as a guide when
selecting the amount of equipment or cargo
your truck can carry. If you are unsure of your
vehicle’s front, rear, or total weight, go to a
weigh station and weigh your vehicle.
Your dealer can also help you with this.
The total vehicle reserve capacity for your
vehicle can be found in the lower right corner
of the Certication/Tire label as shown
previously.
See your dealer for additional advice and
information about using a snow plow on your
vehicle. Also, seeLoading Your Vehicle on
page 409.
Emergency Roof Lamp Provisions
Vehicles with the RPO VYU snow plow prep
package also have an emergency roof lamp
provision package, RPO TRW. Wiring for the
emergency roof lamp is provided in the B-pillar as
shown. SeeAuxiliary Roof Mounted Lamp on
page 226for switch location.
A. Body Side Inner Panel
B. Emergency Roof Lamp Harness
420

Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. SeeScheduled
Maintenance (Gasoline Engine) on page 617for
more information. Things that are especially
important in trailer operation are automatic
transmission uid (don’t overll), engine oil, axle
lubricant, belt, cooling system and brake system.
Each of these is covered in this manual, and
the Index will help you nd them quickly. If you’re
trailering, it’s a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
Trailer Wiring Harness
Your vehicle is equipped with one of the following
wiring harnesses for towing a trailer or hauling
a slide-in camper.
Basic Trailer Wiring
All regular, extended cab and crew cab pickups
have an eight-wire trailer towing harness.For vehicles not equipped with heavy duty
trailering, the harness is clipped to the vehicle’s
frame behind the spare tire mount. The harness
requires the installation of a trailer connector,
which is available through your dealer.
If your trailer is equipped with electric brakes, you
can get a jumper harness (electric trailer brake
control) with a trailer battery feed fuse from
your dealer.
If you need to tow a light-duty trailer with a
standard four-way round pin connector, you can
also get an adapter from your dealer.
456

Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy duty trailering,
the harness is connected to the trailer mounted to
the hitch platform. The eight-wire harness
contains the following trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Light Blue: CHMSL*
Red: Battery Feed**
Dark Blue: Trailer Brake
*The Center High-Mounted Stoplamp (CHMSL)
wire is tied next to the trailer wiring harness for use
with a trailer, slide-in camper or cap.
**If you are charging a remote (non-vehicle)
battery, press the tow/haul mode button located at
the end of the shift lever. This will boost the
vehicle system voltage and properly charge the
battery. If the trailer is too light for tow/haul mode,
you can turn on the headlamps as a second
way to boost the vehicle system voltage and
charge the battery.
457

Camper/Fifth-Wheel Trailer Wiring Package
The eight-wire camper harness is located under
the front edge of the pickup box on the driver’s
side of the vehicle, attached to the frame bracket.
A connector will have to be added to the wiring
harness which connects to the camper.
The eight-wire harness contains the following
camper/trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Light Blue: Center High-Mounted Stoplamp
(CHMSL)
Red: Battery Feed
Dark Blue: Trailer BrakeIf your vehicle is equipped with the “Heavy-Duty
Trailering” option, please refer to “Heavy-Duty
Trailer Wiring Package” earlier in this section.
When the camper-wiring harness is ordered
without the heavy-duty trailering package, an
eight-wire harness with a seven-pin connector and
separate CHMSL connector are located at the
rear of the vehicle and are tied to the vehicle’s
frame.
458

Electric Brake Control Jumper
{CAUTION:
Be sure to use only the correct trailer
brake harness, the one intended for use
on your vehicle. If you use some other
trailer brake harness, even if it seems to
t, your trailer brakes may not work at all.
You could have a crash in which you or
others could be injured. Use only the
trailer brake harness intended for your
vehicle. If it is no longer available to you,
be sure to get a proper replacement from
your dealer.This harness is included with your vehicle as part
of the heavy-duty trailer wiring package.
This harness is for an electric brake controller and
includes a trailer battery feed fuse. It should be
installed by your dealer or a qualied service
center.
459

Fuses and Circuit Breakers
The wiring circuits in your vehicle are protected
from short circuits by a combination of fuses, circuit
breakers and fusible thermal links. This greatly
reduces the chance of res caused by electrical
problems.
Look at the silver-colored band inside the fuse. If
the band is broken or melted, replace the fuse.
Be sure you replace a bad fuse with a new one of
the identical size and rating.
If you ever have a problem on the road and
don’t have a spare fuse, you can borrow one
that has the same amperage. Just pick some
feature of your vehicle that you can get along
without – like the radio or cigarette lighter – and
use its fuse, if it is the correct amperage. Replace
it as soon as you can.
Instrument Panel Fuse Block
The fuse block access
door is on the driver’s
side edge of the
instrument panel.
Pull off the cover to
access the fuse block.
To remove fuses, hold the end of the fuse
between your thumb and index nger and pull
straight out.
You may have spare fuses located behind the
fuse block access door. These can be used
to replace a bad fuse. However, make sure it
is of the correct amperage.
600