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Driving and Operating 341
pickups. Trailer pin box extensions
and sliding fifth-wheel hitch
assemblies can help this condition.
There should be at least 15 cm (6 in)
of clearance between the top of the
pickup box and the bottom of the
trailer shelf that extends over
the box.
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue of
the trailer to help prevent the tongue
from contacting the road if it
becomes separated from the hitch.
Instructions about safety chains
may be provided by the hitch
manufacturer or by the trailer
manufacturer. If the trailer being
towed weighs up to 2 271 kg
(5,000 lb) with a factory-installed
step bumper, safety chains may be
attached to the attaching points on
the bumper; otherwise, safety
chains should be attached to holes
on the trailer hitch platform. Always
leave just enough slack so the
combination can turn. Never allow
safety chains to drag on the ground.
Trailer Brakes
A loaded trailer that weighs more
than 900 kg (2,000 lb) must be
equipped with its own brake system,
with brakes working on all axles.
Trailer braking equipment
conforming to Canadian Standards
Association (CSA) requirement
CAN3-D313, or its equivalent, is
recommended.
State and local regulations may also
require the trailer to have its own
braking system if loaded above a
certain threshold.
Be sure to read and follow the
instructions for the trailer brakes so
they are installed, adjusted, and
maintained properly.
Do not tap into the vehicle's
hydraulic brake system.
Auxiliary Battery
The auxiliary battery provision can
be used to supply electrical power
to additional equipment that may be
added, such as a slide-in camper.
If equipped, this relay will be on the
driver side of the vehicle, next to the
underhood electrical center.Be sure to follow the proper
installation instructions included with
any electrical equipment that is
installed.
Caution
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 of 30 amps for the auxiliary
battery provision.
Trailer Wiring Harness
The 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, double cab, and crew
cab pickups have a seven-wire
trailer towing harness.
For vehicles not equipped with
heavy-duty trailering, the harness is
secured to the vehicle's frame
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342 Driving and Operating
behind the spare tire mount. The
harness requires the installation of a
trailer connector, which is available
through your dealer.
Heavy-Duty Trailer Wiring Harness
Package
For vehicles equipped with
heavy-duty trailering, the harness
connector is mounted in the bumper.
For vehicles with the 5th wheel/
gooseneck trailer package, the
harness connector is mounted on
the inside of the pickup bed behind
the rear wheel.
The seven-wire harness contains
the following trailer circuits:
.Green/Violet: Left Stop/Turn
Signal
. Yellow/Gray: Right Stop/Turn
Signal
. Gray/Brown: Taillamps/Parking
Lamps
. White: Ground
. White/Green: Back-up Lamps .
Red/Green: Battery Feed
. Dark Blue: Trailer Brake
To help charge a remote
(non-vehicle) battery, press the Tow/
Haul Mode button at the end of the
shift lever. If the trailer is too light for
Tow/Haul Mode, turn on the
headlamps to help charge the
battery.
Camper/Fifth-Wheel Trailer Wiring
Package
For vehicles without the 5th wheel/
gooseneck tralier package,
seven-wire camper harness is under
the rear bumper, attached to the
frame near the rear crossmember.
A connector must be added to the
wiring harness that connects to the
camper.
The harness contains the following
camper/trailer circuits:
. Green/Violet: Left Stop/Turn
Signal
. Yellow/Gray: Right Stop/Turn
Signal
. Gray/Brown: Taillamps/Parking
Lamps
GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Driving and Operating 343
.White: Ground
. White/Green: Back-up Lamps
. Red/Green: Battery Feed
. Dark Blue: Trailer Brake
If the vehicle is equipped with the
heavy-duty trailering option, see
“Heavy-Duty Trailer Wiring Harness
Package” earlier in this section.
When the camper-wiring harness is
ordered without the heavy-duty
trailering package, a seven-wire
harness with a seven-pin connector
is at the rear of the vehicle and is
tied to the vehicle's frame.
Electric Brake Control Wiring
Provisions
These wiring provisions are
included with the vehicle as part of
the trailer wiring package. These
provisions are for an electric brake
controller.
The harness should be installed by
your dealer or a qualified service
center.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
cluster comes on when the Tow/
Haul Mode is on. Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See
Tow/Haul
Mode 0292.
Tow/Haul is designed to be most
effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing 0325. Tow/Haul is
most useful under the following
driving conditions:
. When pulling a heavy trailer or a
large or heavy load through
rolling terrain.
. When pulling a heavy trailer or a
large or heavy load in
stop-and-go traffic.
. When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul
when lightly loaded or with no trailer
at all will not cause damage.
However, there is no benefit to the
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Driving and Operating 349
Conversions and
Add-Ons
Add-On Electrical
Equipment
{Warning
The Data Link Connector (DLC) is
used for vehicle service and
Emission Inspection/Maintenance
testing. SeeMalfunction Indicator
Lamp (Check Engine Light)
0 141. A device connected to the
DLC —such as an aftermarket
fleet or driver-behavior tracking
device —may interfere with
vehicle systems. This could affect
vehicle operation and cause a
crash. Such devices may also
access information stored in the
vehicle’s systems.
Caution
Some electrical equipment can
damage the vehicle or cause
components to not work and
would not be covered by the
vehicle warranty. Always check
with your dealer before adding
electrical equipment.
Add-on equipment can drain the
vehicle's 12-volt battery, even if the
vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see
Servicing the Airbag-Equipped
Vehicle 085 and Adding Equipment
to the Airbag-Equipped
Vehicle 085.
For information on wiring auxiliary
switches, see www.gmupfitter.com
or contact your dealer.
Adding a Snow Plow or
Similar Equipment
Caution
Do not exceed 64 km/h (40 mph)
with a snow plow mounted to the
vehicle. The vehicle could
overheat and be damaged.
Before installing a snow plow on the
vehicle, here are some things you
need to know:
Caution
If the vehicle does not have the
snow plow prep package, adding
a plow can damage the vehicle,
and the repairs would not be
covered by warranty. Unless the
vehicle was built to carry a snow
plow, do not add one to the
vehicle. If the vehicle has the
snow plow prep package, called
RPO VYU, then the payload the
vehicle can carry will be reduced (Continued)
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354 Vehicle Care
Vehicle Care
General Information
General Information . . . . . . . . . . 355
California Proposition65 Warning . . . . . . . . . . . . . . . . . 355
California Perchlorate Materials Requirements . . . . . 356
Accessories and Modifications . . . . . . . . . . . . . . . . 356
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 357
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 357
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 358
Engine Oil . . . . . . . . . . . . . . . . . . . . 363
Engine Oil Life System . . . . . . . 366
Automatic Transmission Fluid (6 Speed Transmission) . . . . . 367
Automatic Transmission Fluid (8 Speed Transmission) . . . . . 370
Engine Air Cleaner/Filter . . . . . . 370
Cooling System . . . . . . . . . . . . . . 371
Engine Coolant . . . . . . . . . . . . . . . 373
Engine Overheating . . . . . . . . . . 375
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . 377
Engine Fan . . . . . . . . . . . . . . . . . . . 377 Power Steering Fluid (1500
Series) . . . . . . . . . . . . . . . . . . . . . . 378
Power Steering Fluid (2500/ 3500 Series) . . . . . . . . . . . . . . . . 378
Washer Fluid . . . . . . . . . . . . . . . . . 379
Brakes . . . . . . . . . . . . . . . . . . . . . . . 380
Brake Fluid . . . . . . . . . . . . . . . . . . . 380
Battery - North America . . . . . . 382
Four-Wheel Drive . . . . . . . . . . . . . 382
Front Axle . . . . . . . . . . . . . . . . . . . . 383
Rear Axle . . . . . . . . . . . . . . . . . . . . 384
Noise Control System . . . . . . . . 385
Starter Switch Check . . . . . . . . . 386
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 386
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 387
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 387
Wiper Blade Replacement . . . . 387
Glass Replacement . . . . . . . . . . 388
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 388
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 388
Halogen Bulbs . . . . . . . . . . . . . . . . 388
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 388 LED Lighting . . . . . . . . . . . . . . . . . 389
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 389
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 390
Replacement Bulbs . . . . . . . . . . . 391
Electrical System
High Voltage Devices and Wiring . . . . . . . . . . . . . . . . . . . . . . . 391
Electrical System Overload . . . 391
Fuses . . . . . . . . . . . . . . . . . . . . . . . . 392
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 392
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 395
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 397
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 399
All-Season Tires . . . . . . . . . . . . . . 400
Winter Tires . . . . . . . . . . . . . . . . . . 400
Low-Profile Tires . . . . . . . . . . . . . 401
All-Terrain Tires . . . . . . . . . . . . . . . 401
Tire Sidewall Labeling . . . . . . . . 401
Tire Designations . . . . . . . . . . . . . 404
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 405
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356 Vehicle Care
harm. Engine exhaust, many parts
and systems, many fluids, and
some component wear by-products
contain and/or emit these
chemicals.
SeeBattery - North America 0382
and Jump Starting - North
America 0434.
California Perchlorate
Materials Requirements
Certain types of automotive
applications, such as airbag
initiators, safety belt pretensioners,
and lithium batteries contained in
Remote Keyless Entry transmitters,
may contain perchlorate materials.
Special handling may be necessary.
For additional information, see
www.dtsc.ca.gov/hazardouswaste/
perchlorate.
Accessories and
Modifications
Adding non-dealer accessories or
making modifications to the vehicle
can affect vehicle performance and
safety, including such things as
airbags, braking, stability, ride and
handling, emissions systems,
aerodynamics, durability, and
electronic systems like antilock
brakes, traction control, and stability
control. These accessories or
modifications could even cause
malfunction or damage not covered
by the vehicle warranty.
Damage to suspension components
caused by modifying vehicle height
outside of factory settings will not be
covered by the warranty. Damage to vehicle components
resulting from modifications or the
installation or use of non-GM
certified parts, including control
module or software modifications, is
not covered under the terms of the
vehicle warranty and may affect
remaining warranty coverage for
affected parts.
GM Accessories are designed to
complement and function with other
systems on the vehicle. See your
dealer to accessorize the vehicle
using genuine GM Accessories
installed by a dealer technician.
Also, see
Adding Equipment to the
Airbag-Equipped Vehicle 085.
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Vehicle Care 359
1. Positive (+) Terminal. SeeJump Starting - North
America 0434.
2. Battery - North America 0382.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0371.
4. Engine Air Cleaner/Filter 0370.
5. Automatic Transmission Dipstick (If Equipped). See
“How to Check Automatic
Transmission Fluid” under
Automatic Transmission Fluid
(6 Speed Transmission) 0367
or Automatic Transmission
Fluid (8 Speed
Transmission) 0370.
6. Remote Negative (–) Location. See Jump Starting - North
America 0434.
7. Engine Cooling Fans (Out of View). See Cooling
System 0371.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0363. 9. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil 0363.
10. Brake Fluid Reservoir. See Brake Fluid 0380.
11. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer
Fluid 0379.
12. Engine Compartment Fuse
Block 0392.
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1. Positive (+) Terminal. SeeJump Starting - North
America 0434.
2. Battery - North America 0382.
3. Coolant Surge Tank and Pressure Cap. See Cooling
System 0371.
4. Engine Air Cleaner/Filter 0370.
5. Automatic Transmission Dipstick (If Equipped). See
“How to Check Automatic
Transmission Fluid” under
Automatic Transmission Fluid
(6 Speed Transmission) 0367
or Automatic Transmission
Fluid (8 Speed
Transmission) 0370.
6. Remote Negative (–) Location (Out of View). See Jump
Starting - North America 0434.
7. Engine Cooling Fans (Out of View). See Cooling
System 0371.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0363. 9. Engine Oil Dipstick. See
“Checking Engine Oil” under
Engine Oil 0363.
10. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer
Fluid 0379.
11. Brake Fluid Reservoir. See Brake Fluid 0380.
12. Engine Compartment Fuse
Block 0392.