tow GMC SIERRA 2004 Manual PDF

Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. And, it can also depend
on any special equipment that you have on your vehicle.
Use one of the following charts to determine how
much your vehicle can weigh, based upon your vehicle
model and options.Maximum trailer weight is calculated assuming the
driver and one passenger are in the tow vehicle and it
has all the required trailering equipment. The weight
of additional optional equipment, passengers and cargo
in the tow vehicle must be subtracted from the
maximum trailer weight.
Above the 5,000 lbs. (2 268 kg) trailer rating, the
handling/trailering suspension is required on
C-1500 models and the handling/trailering or off-road
suspension is required on K-1500 models.
Vehicle* Axle Ratio Maximum Trailer Weight GCWR
C-1500 Regular Cab Short Box (2WD)*
4300 V6 (Auto)3.08
3.424,600 lbs. (2 087kg)
5,100 lbs. (2 313kg)9,000 lbs. (4 082 kg)
9,500 lbs. (4 309 kg)
4300 V6 (Manual)3.08
3.423,600 lbs. (1 633 kg)
4,100 lbs. (1 860 kg)8,000 lbs. (3 628 kg)
8,500 lbs. (3 855 kg)
4800 V8 (Auto)3.42
3.736,500 lbs. (2 948 kg)
7,500 lbs. (3 401 kg)11,000 lbs. (4 994 kg)
12,000 lbs. (5 443 kg)
4800 V8 (Manual)3.42
3.734,500 lbs. (2 041 kg)
5,500 lbs. (2 495 kg)9,000 lbs. (4 082 kg)
10,000 lbs. (4 535 kg)
5300 V83.42
3.737,500 lbs. (3 401 kg)
8,500 lbs. (3 855 kg)12,000 lbs. (5 443 kg)
13,000 lbs. (5 897 kg)
* Fifth-wheel or gooseneck kingpin weight 15 percent to 25 percent of trailer weight up to 1,500 lbs. (680 kg)
maximum.
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Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important weight
to measure because it affects the total or gross weight
of your vehicle. The Gross Vehicle Weight (GVW)
includes the curb weight of the vehicle, any cargo you
may carry in it, and the people who will be riding in
the vehicle. If you have a lot of options, equipment,
passengers or cargo in your vehicle, it will reduce the
tongue weight your vehicle can carry, which will
also reduce the trailer weight your vehicle can tow. And
if you will tow a trailer, you must add the tongue load
to the GVW because your vehicle will be carrying
that weight, too. See
Loading Your Vehicle on page 4-57for more information about your vehicle's maximum
load capacity.
The trailer tongue weight (A) should be 10 percent to
15 percent of the total loaded trailer weight, up to
a maximum of 600 lbs. (272 kg) for the 1500 series, and
up to a maximum of 600 lbs. (272 kg) for the
2500 series with a weight carrying hitch. The trailer
tongue weight (A) should be 10 percent to 15 percent of
the total loaded trailer weight, up to a maximum of
1,000 lbs. (453 kg) for the 1500 series and up to
a maximum of 1,500 lbs. (680 kg) for the 2500 series
with a weight distributing hitch.
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Weight Distributing Hitches and Weight
Carrying Hitches
A:Body to Ground Distance
B:Front of VehicleWhen using a weight-distributing hitch, the hitch must
be adjusted so the distance (A) remains the same both
before and after coupling the trailer to the tow vehicle.
If you use a step-bumper hitch, the bumper could
be damaged in sharp turns. Make sure there is ample
room when turning to avoid contact between the
trailer and the bumper.
If you will be pulling a trailer that, when loaded, will
weigh more than 5,000 lbs (2 270 kg) be sure to use a
properly mounted weight-distributing hitch and sway
control of the proper size. This equipment is very
important for proper vehicle loading and good handling
when driving. Always use a sway control if the trailer
will weigh more than these limits. You can ask a
hitch dealer about sway controls.
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Fifth Wheel and Gooseneck Trailering
Fifth wheel and gooseneck trailers can be used with
many pickup models. These trailers place a larger
percentage of the weight (kingpin weight) on the tow
vehicle than conventional trailers. Make sure this weight
does not cause the vehicle to exceed GAWR or GVWR.
Fifth wheel or gooseneck kingpin weight should be 15 to
25 percent of the trailer weight up to the maximum
amount speci®ed in the trailering chart for your vehicle.
See ªWeight of the Trailerº in this section for more
information.
The hitch should be located in the pickup bed so that
it's centerline is over or slightly in front of the rear axle.
Take care that it is not so far forward that it will
contact the back of the cab in sharp turns. This is
especially important for short box pickups. Trailer pin
box extensions and sliding ®fth wheel hitch assemblies
can help this condition. There should be at least six
inches of clearance between the top of the pickup box
and the bottom of the trailer shelf that extends over
the box.
Make sure the hitch is attached to the tow vehicle frame
rails. Do not use the pickup box for support.
Safety Chains
You should always attach chains between your vehicle
and your 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 you are towing a trailer up to 5,000 lbs.
(2 271 kg) with a factory-installed step bumper, you
may attach the safety chains to the attaching points on
the bumper. If you are towing a trailer up to your
vehicle's trailer rating limit you may attach the safety
chains to the attaching point on the hitch platform. If you
are towing with an aftermarket hitch follow the trailer
or hitch manufacturer's recommendation for attaching
safety chains. Always leave just enough slack so
you can turn with your rig. Never allow safety chains to
drag on the ground.
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Trailer Brakes
If your trailer weighs more than 2,000 lbs. (900 kg)
loaded, then it needs its own brakes ± and they must be
adequate. Be sure to read and follow the instructions
for the trailer brakes so you'll be able to install,
adjust and maintain them properly.
Your trailer brake system can tap into the vehicle's
hydraulic brake system only if:
·The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
·The trailer's brake system will use less than
0.02 cubic inch (0.3 cc) of ¯uid from your vehicle's
master cylinder. Otherwise, both braking systems
won't work well. You could even lose your brakes.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the ¯uid
to the rear brakes. But don't use copper tubing for this.
If you do, it will bend and ®nally break off. Use steel
brake tubing.
Driving with a Trailer
{CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon
monoxide (CO) could come into your vehicle.
You can not see or smell CO. It can cause
unconsciousness or death. See
Engine
Exhaust on page 2-53
. To maximize your safety
when towing a trailer:
·Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
·Keep the rear-most windows closed.
·If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle. Do not use
the climate control setting for maximum air
because it only recirculates the air inside
your vehicle. See
Climate Control System
on page 3-21.
4-91

Towing a trailer requires a certain amount of experience.
Before setting out for the open road, you'll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the trailer.
And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector, lamps,
tires and mirror adjustment. If the trailer has electric
brakes, start your vehicle and trailer moving and then
apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
While towing a trailer or when exposed to long periods
of sunshine, the ¯oor of the truck bed may become
very warm. Avoid putting items in the truck bed
that might be affected by high ambient temperatures.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
Passing
You'll need more passing distance up ahead when
you're towing a trailer. And, because you're a good deal
longer, you'll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just 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. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you're turning with a trailer, make wider turns
than normal. Do this so your trailer won't strike
soft shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
4-92

Turn Signals When Towing a Trailer
The arrows on your instrument panel will ¯ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ¯ash, telling other drivers
you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ¯ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It's
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you can tow in
DRIVE (D). You may want to shift the transmission
to lower gear selection if the transmission shifts too often
(e.g., under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode if the
transmission shifts too often. See
Tow/Haul Mode
Light on page 3-53.If you have a 5-speed manual transmission and you are
towing a trailer, it's better not to use FIFTH (5) gear.
Just drive in FOURTH (4) gear (or, as you need
to, a lower gear).
If you have a 6-speed manual transmission and you are
towing a trailer, it's better not to use SIXTH (6) gear.
Drive in FIFTH (5) gear (or, as you need to, a lower gear).
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 you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your 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 PARK (P) for a few
minutes before turning the engine off. For manual
transmissions, let the engine run while parked,
preferably on level ground, with the transmission out of
gear and the parking brake applied, for a few minutes
before turning the engine off. If you do get the overheat
warning, see
Engine Overheating on page 5-36.
4-93

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
·Start your engine
·Shift into a gear
·Release the parking brake
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. SeeScheduled Maintenance on
page 6-4for more information. Things that are especially
important in trailer operation are automatic transmission
¯uid (don't over®ll), engine oil, axle lubricant, belt,
cooling system and brake system. Each of these is
covered in this manual, and the Index will help you ®nd
them quickly. If you're trailering, it's a good idea to
review these sections before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Your 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 crew cab pickups have a
six-wire trailer towing harness.
The six-wire harness is located at the rear of the vehicle
and is tied to the vehicle's frame. The harness requires
the installation of a trailer-wiring harness connector,
which is available through your dealer.
4-95

The six-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: Center High-Mounted Stoplamp
(CHMSL)
If you need to upgrade your trailer wiring harness, an
additional 2±wire harness and 7 pin universal trailer
connector are available from your dealer.
Heavy-DutyTrailer Wiring Harness
Package
Your pickup may be equipped with the eight-wire trailer
towing harness. This harness with a seven-pin
universal trailer connector is attached to a bracket on
the hitch platform.
* 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.
4-96

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
If your trailer is equipped with electric brakes, you can
get a jumper harness (electric trailer brake control)
with a trailer battery feed fuse from your dealer.
If you need to tow a light-duty trailer with a standard
four-way round pin connector you can also get an
adapter from your dealer.
Camper/Fifth-Wheel Trailer Wiring Package
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
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