AUX GMC SIERRA 2008 Owner's Guide

Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy duty trailering, the
harness is connected to a bracket on the hitch platform.
The seven-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
Red: Battery Feed*
Dark Blue: Trailer Brake**The fuses for these two circuits are installed in the
underhood electrical center, but the wires are not
connected. They should be connected by your dealer or
a qualied service center. The fuse and wire for the
ITBC is factory installed and connected if the vehicle is
equipped with an ITBC. The fuse for the battery
feed is not required if your vehicle has an auxiliary
battery. If your vehicle does not have an auxiliary
battery, have your dealer or authorized service center
install the required fuse.
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 and charge
the battery.
4-91

Electric Brake Control Wiring
Provisions
These wiring provisions are included with your vehicle
as part of the trailer wiring package. These provisions
are for an electric brake controller. The instrument panel
contains blunt cut wires near the data link connector
for the trailer brake controller. The harness contains the
following wires:
Dark Blue: Brake Signal to Trailer Connector
Red/Black: Battery
Light Blue/White: Brake Switch
White: Ground
It should be installed by your dealer or a qualied
service center.
If your vehicle is equipped with an ITBC, the blunt cuts
exist, but are not connected further in the harness. If
you install an aftermarket trailer brake controller,
the ITBC must be disconnected. Do not power both
ITBC and aftermarket controllers to control the trailer
brakes at the same time.
Auxiliary Battery
The auxiliary battery provision can be used to supply
electrical power to additional equipment that you
may choose to add, such as a slide-in camper. If your
vehicle has this provision, this relay will be located
on the driver’s side of the vehicle, next to the underhood
electrical center.
Be sure to follow the proper installation instructions that
are included with any electrical equipment that you
install.
Notice:Leaving electrical equipment on for
extended periods will drain the battery. Always turn
off electrical equipment when not in use and do
not use equipment that exceeds the maximum
amperage rating for the auxiliary battery provision.
4-93

Fuses Usage
27 Passenger Side Park Lamps
28 Fog Lamps
29 Horn
30Passenger Side High-Beam
Headlamp
31 Daytime Running Lamps
32 Driver Side High-Beam Headlamp
33 Daytime Running Lights 2
34 Sunroof
35Key Ignition System, Theft Deterrent
System
36 Windshield Wiper
37 SEO B2 Uptter Usage (Battery)
38 Electric Adjustable Pedals
39 Climate Controls (Battery)
40 Airbag System (Ignition)
41 Amplier
42 Audio System
43Miscellaneous (Ignition), Cruise
ControlFuses Usage
44 Not Used
45 Airbag System (Battery)
46 Instrument Panel Cluster
47 Power Take-Off
48Auxiliary Climate Control (Ignition),
Compass-Temperature Mirror
49Center High-Mounted Stoplamp
(CHMSL)
50 Rear Defogger
51 Heated Mirrors
52 SEO B1 Uptter Usage (Battery)
53Cigarette Lighter, Auxiliary Power
Outlet
54Automatic Level Control Compressor
Relay, SEO Uptter Usage
55 Climate Controls (Ignition)
56Engine Control Module, Secondary
Fuel Pump (Ignition)
5-128

Audio System (cont.)
Navigation/Radio System, see Navigation
Manual.................................................3-112
Radio Reception........................................3-125
Rear Seat Audio (RSA)...............................3-122
Setting the Clock.........................................3-81
Theft-Deterrent Feature...............................3-123
XM™ Satellite Radio Antenna System...........3-126
Audio System(s).............................................3-84
Automatic Headlamp System............................3-19
Automatic Transmission
Fluid..................................................5-22, 5-25
Operation...................................................2-28
Auxiliary Roof Mounted Lamp Switch.................3-20
B
Battery..........................................................5-45
Electric Power Management..........................3-22
Run-Down Protection...................................3-23
Brake
Emergencies................................................ 4-5
Brakes..........................................................5-42
System Warning Light..................................3-44
Braking........................................................... 4-3
Braking in Emergencies..................................... 4-5
Break-In, New Vehicle.....................................2-22
Bulb Replacement...........................................5-59Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp............................................5-61
Halogen Bulbs............................................5-59
Headlamp Aiming........................................5-56
Headlamps.................................................5-60
License Plate Lamps....................................5-64
Pickup Box Identication and Fender
Marker Lamps.........................................5-62
Replacement Bulbs......................................5-65
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps........................................5-62
Buying New Tires...........................................5-84
C
Calibration.............................................2-55, 2-57
California Fuel.................................................. 5-7
California Perchlorate Materials Requirements....... 5-5
California Proposition 65 Warning....................... 5-4
Canadian Owners................................................ ii
Capacities and Specications..........................5-130
Carbon Monoxide...................2-14, 2-53, 4-31, 4-55
Care of
Safety Belts..............................................5-115
Cargo Lamp...................................................3-22
Cargo Management System.............................2-78
CD, MP3 ............................................3-102, 3-106
Center Console Storage Area...........................2-76
2

I
Ignition Positions.............................................2-22
Infants and Young Children, Restraints...............1-38
Ination - Tire Pressure...................................5-74
Instrument Panel
Overview...............................................3-4, 3-6
Storage Area..............................................2-75
Instrument Panel (I/P)
Brightness..................................................3-21
Cluster.......................................................3-35
J
Jump Starting.................................................5-46
K
Keyless Entry System....................................... 2-4
Keys............................................................... 2-3
L
Labeling, Tire Sidewall.....................................5-67
Lamps
Auxiliary Roof Mounted Lamp........................3-20
Cargo........................................................3-22
Dome........................................................3-21Lamps (cont.)
Dome Lamp Override...................................3-21
Puddle.......................................................3-20
Reading.....................................................3-22
Lap Belt........................................................1-34
Lap-Shoulder Belt...........................................1-28
LATCH System
Child Restraints...........................................1-45
Latches, Seatback..........................................1-11
License Plate Lamps.......................................5-64
Light
Airbag Off..................................................3-39
Airbag Readiness........................................3-38
Antilock Brake System Warning.....................3-45
Brake System Warning.................................3-44
Charging System.........................................3-43
Cruise Control.............................................3-52
Fog Lamp..................................................3-52
Four-Wheel-Drive.........................................3-53
Highbeam On.............................................3-52
Low Fuel Warning.......................................3-54
Malfunction Indicator....................................3-48
Oil Pressure...............................................3-51
Passenger Airbag Status Indicator..................3-41
Safety Belt Reminders..................................3-37
Security.....................................................3-52
StabiliTrak
®Indicator....................................3-46
Tire Pressure..............................................3-47
Tow/Haul Mode...........................................3-53
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