trailer GMC SIERRA DENALI 2010 Service Manual

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

If No Steam Is Coming From The
Engine Compartment
The ENGINE OVERHEATED STOP ENGINE or the
ENGINE OVERHEATED IDLE ENGINE message, along
with a low coolant condition, can indicate a serious
problem.
If an engine overheat warning is displayed but no steam
can be seen or heard, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.
.Idles for long periods in traffic.
.Tows a trailer. SeeTowing a Trailer on page 5‑42.
If the overheat warning is displayed with no sign of
steam: 1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral) while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let the
engine idle. If the temperature overheat gage is no longer in the
overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drive
the vehicle slow for about 10 minutes. Keep a safe
vehicle distance from the car in front of you. If the
warning does not come back on, continue to drive
normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is no sign of steam, idle the engine for
three minutes while parked. If the warning is still
displayed, turn off the engine until it cools down. Also,
see
“Overheated Engine Protection Operating Mode”
later in this section.
6-36

Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
ENGINE POWER IS REDUCED message is displayed,
an overheat protection mode which alternates firing
groups of cylinders helps prevent engine damage. In
this mode, you will notice a loss in power and engine
performance. This operating mode allows the vehicle to
be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil and
reset the oil life system. See Engine Oil
on
page 6‑18.
Engine Fan Noise
The vehicle has electric cooling fans. You might hear
the fans spinning at low speed during most everyday
driving. The fans can turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or high
outside temperatures, or if you are operating the air
conditioning system, the fans can change to high speed
and you might hear an increase in fan noise. This is
normal and indicates that the cooling system is
functioning properly. The fans change to low speed
when additional cooling is no longer required.
6-37

FusesUsage
1 Right Trailer Stop/Turn Lamp
2Electronic Suspension Control,
Automatic Level Control Exhaust
3 Left Trailer Stop/Turn Lamp
4 Engine Controls
5 Engine Control Module, Throttle
Control
6 Trailer Brake Controller
7 Front Washer
8 Oxygen Sensor
9 Antilock Brakes System 2
10 Trailer Back-up Lamps 11 Driver Side Low-Beam Headlamp
12 Engine Control Module (Battery)
13 Fuel Injectors, Ignition Coils
(Right Side)
14 Transmission Control Module
(Battery)
Fuses
Usage
15 Vehicle Back-up Lamps
16 Passenger Side Low-Beam Headlamp
17 Air Conditioning Compressor
18 Oxygen Sensors
19 Transmission Controls (Ignition)
20 Fuel Pump
21 Fuel System Control Module
22 Not Used
23 Not Used
24Fuel Injectors, Ignition Coils
(Left Side)
25 Trailer Park Lamps
26 Driver Side Park Lamps
27 Passenger Side Park Lamps
28 Fog Lamps
29 Horn
30 Passenger Side High-Beam
Headlamp
6-119

J-Case FusesUsage
57 Cooling Fan 1
58 Not Used
59 Heavy Duty Antilock Brake System
60 Cooling Fan 2
61 Antilock Brake System 1
62 Starter
63 Stud 2 (Trailer Brakes)
64 Left Bussed Electrical Center 1
65 Not Used
66 Heated Windshield Washer System
67 Transfer Case
68Stud 1 (Trailer Connector Battery
Power) (Optional - 40A Fuse
Required)
69 Mid-Bussed Electrical Center 1
70 Climate Control Blower
71 Not Used
72 Left Bussed Electrical Center 2
Relays Usage
FAN HI Cooling Fan High Speed
FAN LO Cooling Fan Low Speed
FAN CNTRL Cooling Fan Control
HDLP LO/HID Low-Beam Headlamp
FOG LAMP Front Fog Lamps
A/C CMPRSR Air Conditioning Compressor
STRTR Starter
PWR/TRN Powertrain
FUEL PMP Fuel Pump
PRK LAMP Parking Lamps
REAR DEFOG Rear Defogger
RUN/CRANK Switched Power
6-121

First Engine Oil Change After Every
40 000 km/25,000 Miles
.Fuel system inspection for damage or leaks.
First Engine Oil Change After Every
80 000 km/50,000 Miles
.Engine air cleaner filter replacement. SeeEngine
Air Cleaner/Filter on page 6‑22.
.Automatic transmission fluid change (severe
service) for vehicles mainly driven in heavy city
traffic in hot weather, in hilly or mountainous
terrain, when frequently towing a trailer, or used for
taxi, police, or delivery service. See Automatic
Transmission Fluid on page 6‑24.
.Transfer case fluid change (severe service) for
vehicles mainly driven when frequently towing a
trailer, or used for taxi, police, or delivery service.
Check vent hose at transfer case for kinks and
proper installation. Check to be sure vent hose is
unobstructed, clear, and free of debris. During any maintenance, if a power washer is used to clean
mud and dirt from the underbody, care should be
taken to not directly spray the transfer case output
seals. High pressure water can overcome the seals
and contaminate the transfer case fluid.
Contaminated fluid will decrease the life of the
transfer case and should be replaced.
.Evaporative control system inspection. Check all
fuel and vapor lines and hoses for proper hook‐up,
routing, and condition. Check that the purge valve,
if the vehicle has one, works properly. Replace as
needed.
An Emission Control Service. The U.S.
Environmental Protection Agency or the California
Air Resources Board has determined that the
failure to perform this maintenance item will not
nullify the emission warranty or limit recall liability
prior to the completion of the vehicle's useful life.
We, however, urge that all recommended
maintenance services be performed at the
indicated intervals and the maintenance be
recorded.
7-6

Headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Daytime Running Lamps (DRL) . . . . . . . . . . . . . . . . . . . 4-11
Exterior Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
High/Low Beam Changer . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
On Reminder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Heated Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-5
Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17, 4-20 Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
High-Speed Operation, Tires . . . . . . . . . . . . . . . . . . . . . . 6-72
Highbeam On Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
Highway Hypnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26
Hill and Mountain Roads . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26
Hood Checking Things Under . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-3
How to Wear Safety Belts Properly . . . . . . . . . . . . . . . . 2-16I
Ignition Positions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
Infants and Young Children, Restraints . . . . . . . . . . . . 2-36
Inflation - Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-71
Instrument Panel Brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Storage Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-58
Instrument Panel Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . 4-28
Integrated Trailer Brake Control System (ITBC) . . . . 5-42
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-2
J
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44
K
Keyless Entry Remote (RKE) System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Keyless Entry System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-4
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
i - 8