trailer CHEVROLET SILVERADO 2008 2.G Repair Manual

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.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”
later in this section.
When towing at high elevation on steep uphill grades,
consider the following: Engine coolant at higher
elevations will boil at a lower temperature than at or
near sea level. If you turn your engine off immediately
after towing at high elevation 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 transmission
in PARK (P) at least ve minutes before turning the
engine off. If you do get the overheat warning, see
Engine Overheating on page 5-32.
4-88

Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet.
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 regular brakes. Then apply your
parking brake and shift into PARK (P).
5. If you have a four-wheel-drive vehicle, be sure the
transfer case is in a drive gear and not in
NEUTRAL.
6. Release the regular brakes.
{CAUTION:
It can be dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P) with
the parking brake rmly set. Your vehicle
can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle will not move,
even when you are on fairly level ground, use
the steps that follow.
Always put the shift lever fully in PARK (P)
with the parking brake rmly set.
If the transfer case on four-wheel-drive vehicles
is in NEUTRAL, your vehicle will be free to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear — not in
NEUTRAL.
4-89

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 (Gasoline
Engine) on page 6-4for more information. Things
that are especially important in trailer operation are
automatic transmission uid (don’t overll), 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 and crew cab pickups have a
seven-wire trailer towing harness.
For vehicles not equipped with heavy duty trailering, the
harness is clipped 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 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.
4-90

Heavy-Duty Trailer 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 qualied 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 your vehicle has an auxiliary
battery. If your vehicle does not have an auxiliary
battery, have your dealer or authorized service center
install the required fuse.
If you are 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, you can turn on the headlamps as
a second way to boost the vehicle system and charge
the battery.
4-91

Camper/Fifth-Wheel Trailer Wiring Package
The seven-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 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
Red: Battery Feed
Dark Blue: Trailer BrakeIf your vehicle is equipped with the “Heavy-Duty
Trailering” option, please refer to “Heavy-Duty Trailer
Wiring Package” 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 is located at the rear of the
vehicle and is tied to the vehicle’s frame.
4-92

Electric Brake Control Wiring
Provisions
These wiring provisions are included with your 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 or a qualied
service center.
If your vehicle is equipped with an ITBC, the blunt cuts
exist, but are not connected further in the harness. If
you install an aftermarket trailer brake controller,
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 you may
choose to add, such as a slide-in camper. If your vehicle
has this provision, this relay will be located on the driver’s
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 you install.
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.
Trailer Recommendations
You must subtract your hitch loads from the CWR for
your vehicle. Weigh your vehicle with the trailer
attached, so that you won’t go over the GVWR or
GAWR. If you are using a weight-distributing hitch,
weigh the vehicle without the spring bars in place.
You’ll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information, seeTowing a Trailer on
page 4-55.
4-93

Consistency of Readings
Always check the uid level at least twice using the
procedures described. Consistency (repeatable
readings) is important to maintaining proper uid level.
If uid is added, it may take 15 minutes or longer to
obtain an accurate reading because of residual
uid draining down the dipstick tube. If inconsistent
readings persist, check the transmission breather to be
sure it is clean and not clogged. If readings are still
inconsistent, contact your dealer/retailer.
Automatic Transmission Fluid
(4-Speed Transmission)
When to Check and Change
Automatic Transmission Fluid
A good time to check your automatic transmission uid
level is when the engine oil is changed.
Change the uid and lter at the intervals listed in
Additional Required Services on page 6-6, and be sure
to use the transmission uid listed inRecommended
Fluids and Lubricants on page 6-14.
How to Check Automatic
Transmission Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
5-26

Notice:If your engine catches re because you
keep driving with no coolant, your vehicle can
be badly damaged. The costly repairs would not be
covered by your warranty. SeeOverheated Engine
Protection Operating Mode (V8 Engines Only)
on page 5-34for information on driving to a safe
place in an emergency.
If No Steam Is Coming From
Your Engine
The ENGINE OVERHEATED STOP ENGINE or the
ENGINE OVERHEATED IDLE ENGINE message,
along with a low coolant condition, can indicate a
serious problem.
If you get an engine overheat warning, but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on page 4-55.If you get the ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE message
with no sign of steam, try this for a minute or so:
1. If you have an air conditioner and it is on, turn it off.
2. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
3. If you are stopped in a traffic jam, apply the brake,
shift to N (NEUTRAL); otherwise, shift to the highest
gear while driving — D (DRIVE) or 3 (THIRD).
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
5-33

If the warning continues, pull over, stop, and park your
vehicle immediately.
If there is still no sign of steam and your vehicle has an
engine-driven cooling fan, push down the accelerator
until the engine speed is about twice as fast as normal
idle speed for at least ve minutes while you are parked.
If there is still no sign of steam and your vehicle has an
electric cooling fan, idle the engine for ve minutes
while you are parked.
If you still have the warning, turn off the engine and
get everyone out of the vehicle until it cools down.
Also, see “Overheated Engine Protection Operating
Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.Overheated Engine Protection
Operating Mode (V8 Engines Only)
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed,
an overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage.
In this mode, you will notice a loss in power and engine
performance. This operating mode allows your 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. SeeEngine Oil (Gasoline
Engine) on page 5-15.
5-34

Engine Fan Noise
If your vehicle has a clutched engine cooling fan, when
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing, and/or high outside temperatures, the fan
speed increases as the clutch more fully engages, so
you may hear an increase in fan noise. This is normal
and should not be mistaken as the transmission slipping
or making extra shifts. It is merely the cooling system
functioning properly. The fan will slow down when
additional cooling is not required and the clutch
disengages.You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating your
air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
5-40