2010 GMC SIERRA DENALI Owners Manual

Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving the vehicle without a trailer.
This can help to avoid heavy braking and sudden turns.
Passing
More passing distance is needed when towing a trailer.
The combination will not accelerate as quickly and is
longer so it is necessary to go much farther beyond the
passed vehicle before returning to the lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, move that hand to
the left. To move the trailer to the right, move your hand
to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. The vehicle could be damaged. Avoid
making very sharp turns while trailering.
When turning with a trailer, make wider turns than
normal. Do this so the trailer will not strike soft
shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn out, the arrows on the
instrument panel will still flash for turns. It is important to
check occasionally to be sure the trailer bulbs are still
working.
5-57

Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might get hot and no
longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. See Tow/Haul Mode on page 3‑32.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If the engine
is turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar
to engine overheating. To avoid this, let the engine run
while parked, preferably on level ground, with the
automatic transmission in P (Park) for a few minutes
before turning the engine off. If the overheat warning
comes on, see Engine Overheating on page 6‑34.
Parking on Hills
{WARNING:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can be
injured, and both the vehicle and the trailer can be
damaged. When possible, always park the rig on
a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do not shift into P (Park) yet. Turn the wheels into the curb if facing downhill
or into traffic if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular brakes until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift into P (Park).
5. Release the brake pedal.
5-58

{WARNING:
It can be dangerous to get out of the vehicle if the
shift lever is not fully in P (Park) with the parking
brake firmly set. The vehicle can roll.
If the engine has been left running, the vehicle
can move suddenly. You or others could be
injured. To be sure the vehicle will not move, even
when on fairly level ground, always put the shift
lever fully in P (Park) with the parking brake
firmly set.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine
3. Shift into a gear
4. Release the parking brake
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store thechocks.
Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual's Maintenance Schedule or
Index for more information. Things that are especially
important in trailer operation are automatic transmission
fluid, engine oil, axle lubricant, belts, cooling system
and brake system. It is a good idea to inspect these
before and during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
5-59

Trailer Wiring Harness
Heavy-Duty Trailer Wiring Harness Package
The vehicle has a seven-pin universal heavy-duty trailer
connector attached to the rear bumper beam next to the
integrated trailer hitch.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/
retailer or a qualified service center.
If 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, turn on the headlamps as a second way
to boost the vehicle system and charge the battery.
5-60

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 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/retailer or a
qualified service center.
If the vehicle is equipped with an ITBC, the blunt cuts
exist, but are not connected further in the harness. If an
aftermarket trailer brake controller is installed, the ITBC
must be disconnected. Do not power both ITBC and
aftermarket controllers to control the trailer brakes at the
same time.
Trailer Recommendations
Subtract the hitch loads from the Cargo Weight Rating
(CWR). CWR is the maximum weight of the load the
vehicle can carry. It does not include the weight of the
people inside, but you can figure about 150 lbs. (68 kg)
for each passenger. The total cargo load must not be
more than the vehicles CWR.
Weigh the vehicle with the trailer attached, so the
GVWR or GAWR are not exceeded. If using a
weight-distributing hitch, weigh the vehicle without the
spring bars in place.
The best performance is obtained by correctly
spreading out the weight of the load and choosing the
correct hitch and trailer brakes.
For more information see Towing a Trailer
on
page 5‑42.
5-61

2NOTES
5-62

Section 6 Service and Appearance Care
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Accessories and Modifications . . . . . . . . . . . . . . . . . . 6-4
California Proposition 65 Warning . . . . . . . . . . . . . . . 6-5
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Doing Your Own Service Work . . . . . . . . . . . . . . . . . . 6-5
Adding Equipment to the Outside of the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Fuel E85 (85% Ethanol) . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . 6-10
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-13
Checking Things Under the Hood . . . . . . . . . . . . . . .6-14
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-16
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-22
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . 6-24
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28 Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29
Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34
Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37
Engine Fan Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-39
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-43
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-49
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-50
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Taillamps, Turn Signal, Stoplamps and Back-up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
License Plate Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Windshield Wiper Blade Replacement . . . . . . . . . . .6-61
6-1

Section 6 Service and Appearance Care
Tires. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-62
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . . . . 6-63
Tire Terminology and Definitions . . . . . . . . . . . . . . . 6-68
Inflation - Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . 6-71
High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . . 6-72
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . 6-73
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . 6-74
Tire Inspection and Rotation . . . . . . . . . . . . . . . . . . . 6-78
When It Is Time for New Tires . . . . . . . . . . . . . . . . . 6-79
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-80
Different Size Tires and Wheels . . . . . . . . . . . . . . . 6-82
Uniform Tire Quality Grading . . . . . . . . . . . . . . . . . . . 6-82
Wheel Alignment and Tire Balance . . . . . . . . . . . . 6-84
Wheel Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-84
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-85
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-85
Changing a Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-86
Removing the Spare Tire and Tools . . . . . . . . . . . . 6-88
Removing the Flat Tire and Installing the Spare Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-92
Secondary Latch System . . . . . . . . . . . . . . . . . . . . . . 6-97
Storing a Flat or Spare Tire and Tools . . . . . . . . 6-100
Spare Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-104 Appearance Care
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-105
Interior Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-105
Fabric/Carpet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-106
Leather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-107
Instrument Panel, Vinyl, and Other Plastic Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-107
Wood Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-108
Care of Safety Belts . . . . . . . . . . . . . . . . . . . . . . . . . . 6-108
Weatherstrips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-108
Washing Your Vehicle . . . . . . . . . . . . . . . . . . . . . . . . 6-108
Cleaning Exterior Lamps/Lenses . . . . . . . . . . . . . 6-109
Finish Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-109
Windshield and Wiper Blades . . . . . . . . . . . . . . . . . 6-110
Aluminum or Chrome-Plated Wheels and Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-110
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-111
Sheet Metal Damage . . . . . . . . . . . . . . . . . . . . . . . . . 6-111
Finish Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-112
Underbody Maintenance . . . . . . . . . . . . . . . . . . . . . . 6-112
Chemical Paint Spotting . . . . . . . . . . . . . . . . . . . . . . 6-112
6-2