CHECK TRAILER WIRING–This message will be
displayed if:
1. The ITBC system first determines connection to a trailer with electric brakes and then the trailer
harness becomes disconnected from the vehicle.
If the disconnect occurs while the vehicle is
stationary, this message will automatically turn off
in about thirty seconds. This message will also turn
off if the driver acknowledges this message off or if
the trailer harness is re-connected.
If the disconnect occurs while the vehicle is
moving, this message will continue until the ignition
is turned off. This message will also turn off if the
driver acknowledges this message off or if the
trailer harness is re-connected.
2. There is an electrical fault in the wiring to the electric trailer brakes. This message will continue
as long as there is an electrical fault in the trailer
wiring. This message will also turn off if the driver
acknowledges this message off.
To determine if the electrical fault is on the vehicle side
or trailer side of the trailer wiring harness connection,
do the following: 1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition OFF. 3. Wait ten seconds, then turn the ignition back
to RUN.
4. If the CHECK TRAILER WIRING message re-appears, the electrical fault is on the
vehicle side.
If the CHECK TRAILER WIRING message only
re-appears when connecting the trailer wiring
harness to the vehicle, the electrical fault is on the
trailer side.
SERVICE TRAILER BRAKE SYSTEM –This message
will be displayed when there is a problem with the ITBC
system. If this message persists over multiple ignition
cycles there is a problem with the ITBC system. Take
the vehicle to an authorized GM dealer to have the
ITBC system diagnosed and repaired.
If either the CHECK TRAILER WIRING or SERVICE
TRAILER BRAKE SYSTEM message is displayed while
driving the vehicle, power is no longer available to the
trailer brakes. When traffic conditions allow, carefully
pull the vehicle over to the side of the road and turn the
ignition off. Check the wiring connection to the trailer
and turn the ignition back on. If either of these
messages continues, either the vehicle or trailer needs
service.
5-71
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.
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, extended 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 behind the
spare tire mount. The harness requires the installation
of a trailer connector, which is available through your
dealer.
If towing a light‐duty trailer with a standard four‐way
round pin connector, an adapter is available from your
dealer.
5-75
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 qualified 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 the vehicle has an auxiliary battery. If the
vehicle does not have an auxiliary battery, have your
dealer or authorized service center install the
required fuse.
If charging a remote (non-vehicle) battery, press the
Tow/Haul mode button, if equipped, 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, or the vehicle is not
equipped with Tow/Haul, turn on the headlamps as a
second way to boost the vehicle system and charge the
battery.
5-76
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 behind the steering column 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 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.
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 the vehicle has this
provision, this relay will be located on the drivers 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 is
installed.
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.
5-78
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Fuel E85 (85% Ethanol) . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . 6-11
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-13
Checking Things Under the Hood . . . . . . . . . . . . . . .6-14
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-16
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-21 Automatic Transmission Fluid (4-Speed
Transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23
Automatic Transmission Fluid (6-Speed Transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29
Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-31
Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34
Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36
Engine Fan Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-38
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-43
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-50
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Noise Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
Tampering with Noise Control System Prohibited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-54
6-1
Section 6 Service and Appearance Care
Bulb Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
Pickup Box Identification and Fender Marker Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-59
Taillamps, Turn Signal, Stoplamps and Back-up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
License Plate Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-62
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-62
Windshield Wiper Blade Replacement . . . . . . . . . . .6-63
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-64
Tire Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . . . . 6-65
Tire Terminology and Definitions . . . . . . . . . . . . . . . 6-70
Inflation - Tire Pressure . . . . . . . . . . . . . . . . . . . . . . . . 6-73
High-Speed Operation . . . . . . . . . . . . . . . . . . . . . . . . . 6-74
Dual Tire Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-75
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . 6-75
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . 6-76
Tire Inspection and Rotation . . . . . . . . . . . . . . . . . . . 6-80
When It Is Time for New Tires . . . . . . . . . . . . . . . . . 6-82
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-83
Different Size Tires and Wheels . . . . . . . . . . . . . . . 6-85 Uniform Tire Quality Grading . . . . . . . . . . . . . . . . . . . 6-85
Wheel Alignment and Tire Balance . . . . . . . . . . . . 6-87
Wheel Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-87
Tire Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-89
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-89
Changing a Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-90
Removing the Spare Tire and Tools . . . . . . . . . . . . 6-92
Removing the Flat Tire and Installing the
Spare Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-97
Secondary Latch System . . . . . . . . . . . . . . . . . . . . . 6-103
Storing a Flat or Spare Tire and Tools . . . . . . . . 6-106
Spare Tire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-109
Appearance Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-110
Interior Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-110
Fabric/Carpet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-111
Leather . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-112
Instrument Panel, Vinyl, and Other Plastic Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-112
Care of Safety Belts . . . . . . . . . . . . . . . . . . . . . . . . . . 6-112
Weatherstrips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-113
Washing Your Vehicle . . . . . . . . . . . . . . . . . . . . . . . . 6-113
Cleaning Exterior Lamps/Lenses . . . . . . . . . . . . . 6-113
Finish Care . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-114
Windshield and Wiper Blades . . . . . . . . . . . . . . . . . 6-114
6-2
Section 6 Service and Appearance Care
Aluminum or Chrome-Plated Wheelsand Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-115
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-116
Sheet Metal Damage . . . . . . . . . . . . . . . . . . . . . . . . . 6-116
Finish Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-116
Underbody Maintenance . . . . . . . . . . . . . . . . . . . . . . 6-116
Chemical Paint Spotting . . . . . . . . . . . . . . . . . . . . . . 6-116
Vehicle Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-117
Vehicle Identification Number (VIN) . . . . . . . . . . . 6-117
Service Parts Identification Label . . . . . . . . . . . . . 6-117 Electrical System
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-117
Add-On Electrical Equipment . . . . . . . . . . . . . . . . . 6-117
Windshield Wiper Fuses . . . . . . . . . . . . . . . . . . . . . . 6-118
Power Windows and Other Power Options . . . 6-118
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . . 6-118
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . 6-119
Center Instrument Panel Fuse Block . . . . . . . . . 6-121
Underhood Fuse Block . . . . . . . . . . . . . . . . . . . . . . . 6-122
Capacities and Specifications . . . . . . . . . . . . . . . . . .6-126
6-3
Service
For service and parts needs, visit your dealer. You will
receive genuine GM parts and GM-trained and
supported service people.
Genuine GM parts have one of these marks:
Accessories and Modifications
When non‐dealer/non‐retailer accessories are added to
the vehicle, they 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.
Some of these accessories could even cause
malfunction or damage not covered by the vehicle
warranty.
Damage to vehicle components resulting from the
installation or use of non‐GM certified parts, including
control module 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. Your GM
dealer can accessorize the vehicle using genuine GM
Accessories. When you go to your GM dealer and ask
for GM Accessories, you will know that GM-trained and
supported service technicians will perform the work
using genuine GM Accessories.
Also, seeAdding Equipment to Your Airbag-Equipped
Vehicle on page 2‑92.
6-4