Page 320 of 497
4-92
Heavy-Duty Trailer Wiring Package (If Equipped)
Your pickup may be equipped with the eight-wire trailer
towing harness. This harness with a seven
-pin universal
heavy
-duty trailer connector is attached to a bracket on
the platform hitch.*
* The Center High
-Mounted Stoplamp (CHMSL) wire
is tied next to the trailer wiring harness for use with a
trailer, slide
-in camper or cap.The eight
-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
Light Blue: CHMSL
Red: Battery Feed
Dark Blue: Trailer Brake
A jumper harness for an electric trailer brake controller
and a trailer battery feed fuse are included with this
trailering package. (See ªInstrument Panel Jumper
Wiring Harnessº later in this section.)
If you need to tow a light
-duty trailer with a standard
four
-way round pin connector, an adapter connector is
included with your vehicle.
Page 321 of 497

4-93
Camper/Fifth-Wheel Trailer Wiring Package
(If Equipped)
The eight
-wire camper harness is located under the
front edge of the pickup box on the driver's side of the
vehicle, attached to the frame bracket. A connector will
have to be added to the wiring harness which connects
to the camper.
The eight
-wire harness contains the following
camper/trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back
-up Lamps
Light Blue: Center High
-Mounted
Stoplamp (CHMSL)
Red: Battery Feed
Dark Blue: Trailer Brake
A jumper harness for an electric trailer brake controller
and a trailer battery feed fuse are included with this
trailering package. (See ªInstrument Panel Jumper
Wiring Harnessº later in this section.)
If your vehicle is equipped with the ªHeavy-Duty
Traileringº option, please refer to ªHeavy
-Duty Trailer
Wiring Packageº, earlier in this section.
When the camper
-wiring harness is ordered without the
heavy
-duty trailering package, an eight-wire harness
with a seven
-pin connector and separate CHMSL
connector are located at the rear of the vehicle and are
tied to the vehicle's frame.
Page 322 of 497
4-94
Instrument Panel Jumper Wiring Harness
This harness is included with the heavy-duty and
camper/fifth
-wheel trailer wiring packages. The harness
is for an electric trailer brake controller and includes a
trailer battery feed fuse. This harness and fuse should be
installed by your dealer or a qualified service center.Four Wire Trailer Harness Adapter
If you need to tow a light
-duty trailer with a standard
four
-way round pin connector, an adapter connector is
included with your vehicle.
Connect the adapter with
the tab (arrow) pointing
towards the top. The cap
on the wiring harness will
lock onto the tab (arrow)
and help hold the adapter
in place.
Page 323 of 497
4-95 Auxiliary Battery (If Equipped)
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 passenger's
side of the vehicle, next to
the auxiliary battery.
When using this provision, connection should only be
made to the upper stud (A) of the relay. Do not make
connections to the lower stud (B) of the relay.The auxiliary battery circuit is protected by a megafuse
located behind the auxiliary battery.
Be sure to follow the proper installation instructions
that are included with any electrical equipment that
you install.
NOTICE:
When using the auxiliary battery provision, the
electrical load must not exceed 30 amps. Always
turn off any electrical equipment when not in use.
Leaving electrical equipment on for extended
periods will drain your battery.
Page 368 of 497

6-3
CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.
Be sure you have sufficient knowledge,
experience, the proper replacement parts
and tools before you attempt any vehicle
maintenance task.
Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you use
the wrong fasteners, parts can later break
or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airflow around it. This may cause wind noise
and affect windshield washer performance. Check with
your dealer before adding equipment to the outside of
your vehicle.
Fuel (Gasoline Engine)
If your vehicle has a diesel engine, see ªDiesel Fuel
Requirements and Fuel Systemº in the Diesel Engine
Supplement. For vehicles with gasoline engines, please
read this.
Gasoline Octane
Use regular unleaded gasoline with a posted octane of
87 or higher. If the octane is less than 87, you may get a
heavy knocking noise when you drive. If it is bad
enough, it can damage your engine. A little pinging
noise when you accelerate or drive uphill is considered
normal. This does not indicate a problem exists or that a
higher
-octane fuel is necessary.
Page 375 of 497
6-10 Engine Compartment Overview
When you lift up the hood on the VORTEC 4300 V6 engine, you'll see the following:
A. Engine Air Cleaner/Filter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator
D. Engine Oil Dipstick
E. Automatic Transmission Dipstick
(If Equipped)F. F a n
G. Engine Oil Fill
H. Power Steering Fluid Reservoir
I. Remote Negative (
-)
Terminal (GND)
J. Remote Positive (+) TerminalK. Brake Fluid Reservoir
L. Clutch Fluid Reservoir
(If Equipped)
M. Underhood Fuse Block
N. Battery
O. Windshield Washer Fluid Reservoir
Page 376 of 497
6-11
When you lift up the hood on the VORTEC 5300 V8 engine (VORTEC 4800 and 6000 V8 engines similar), you will
see the following:
A. Engine Air Cleaner/Filter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator
D. Engine Oil Dipstick
E. Automatic Transmission Dipstick
(If Equipped)F. Engine Oil Fill
G. Fan
H. Remote Negative (
-)
Terminal (GND)
I. Power Steering Fluid Reservoir
J. Remote Positive (+) TerminalK. Brake Fluid Reservoir
L. Clutch Fluid Reservoir
(If Equipped)
M. Underhood Fuse Block
N. Battery
O. Windshield Washer Fluid Reservoir
Page 377 of 497
6-12
When you lift up the hood on the VORTEC 8100 V8 engine you will see the following:
A. Engine Air Cleaner/Filter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator
D. Engine Oil Dipstick
E. Automatic Transmission Dipstick
(If Equipped)F. Engine Oil Fill
G. Fan
H. Remote Negative (
-)
Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid ReservoirK. Brake Fluid Reservoir
L. Clutch Fluid Reservoir
(If Equipped)
M. Underhood Fuse Block
N. Battery
O. Windshield Washer Fluid Reservoir