trailer HUMMER H3 2009 Owner's Manual

Safety Chains
Always attach chains between the
vehicle and the 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. Always leave just enough
slack so the rig can turn. Never
allow safety chains to drag on the
ground.
Trailer Brakes
A loaded trailer that weighs more
than 1,500 lbs (680 kg) needs
to have its own brake system that is
adequate for the weight of the
trailer. Be sure to read and follow
the instructions for the trailer brakes
so they are installed, adjusted
and maintained properly.
Driving with a Trailer
Towing a trailer requires a certain
amount of experience. Get to
know the rig before setting out for
the open road. Get acquainted
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
longer and not as responsive as the
vehicle is by itself.
Before starting, check all trailer hitch
parts and attachments, safety
chains, electrical connectors, lamps,
tires and mirror adjustments. If
the trailer has electric brakes, start
the vehicle and trailer moving
and then apply the trailer brake
controller by hand to be sure
the brakes are working. This checks
the electrical connection at the
same time.
During the trip, check occasionally
to be sure that the load is secure,
and that the lamps and any
trailer brakes are still working.
Following Distance
Stay at least twice as far behind
the vehicle ahead as you would
when driving the vehicle without a
trailer. This can help to avoid
situations that require heavy braking
and sudden turns.
Passing
More passing distance is needed
when towing a trailer. Because
the rig is longer, it is necessary to
go much farther beyond the
passed vehicle before returning to
the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. Then, to move
the trailer to the left, 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.
4-48 Driving Your Vehicle

Making Turns
Notice:Making very sharp turns
while trailering could cause
the trailer to come in contact with
the vehicle. The vehicle could
be damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer won’t strike soft
shoulders, curbs, road signs, trees
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a
Trailer
The arrows on the instrument panel
ash whenever signaling a turn
or lane change. Properly hooked up,
the trailer lamps also ash, telling
other drivers the vehicle is turning,
changing lanes or stopping.When towing a trailer, the arrows
on the instrument panel ash
for turns even if the bulbs on the
trailer are burned out. For this
reason you may think other drivers
are seeing the signal when they
are not. It is important to check
occasionally to be sure the trailer
bulbs are still working.
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 have to be used so
much that they would get hot and no
longer work well.
Vehicles with an automatic
transmission 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. For vehicles with
a manual transmission, it is
better not to use the highest 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 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. For vehicles with 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 the
overheat warning comes on,
seeEngine Overheating on
page 5-27.
Driving Your Vehicle 4-49

Parking on Hills
{CAUTION
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 at surface.
If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet for
vehicles with an automatic
transmission, or into gear for
vehicles with a manual
transmission. 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 brake pedal
until the chocks absorb the load.
4. Reapply the brake pedal.
Then apply the parking brake and
shift into P (Park) for vehicles
with an automatic transmission or
into gear for vehicles with a
manual transmission.
5. Release the brake pedal.
Leaving After Parking on
a Hill
The vehicle has a Hill Start Assist
feature, which may be useful
when stopped on a grade. See
Braking on page 4-3for more
information.
1. Apply and hold the brake pedal
while you:
start the engine,
shift into a gear, and
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.
4-50 Driving Your Vehicle

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 uid, 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
Light-Duty Trailer Wiring Package
If the vehicle does not have a
trailer towing package, the chassis
harness will contain the following
blunt cut circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn
Signal
White: Ground
Brown: Tail Lamps
To add a trailer towing wiring
package, have it installed by your
dealer/retailer or a qualied
service center. Also, seeAdd-On
Electrical Equipment on page 5-91
for more information.Heavy-Duty Trailer Wiring
Package
If the vehicle has a trailer towing
package, the rear bumper harness
will have a seven-pin universal
heavy-duty trailer connector
attached to a bracket on the hitch
platform.
Driving Your Vehicle 4-51

The trailer towing harness contains
the following seven 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
If charging a remote (non-vehicle)
battery, turn on the headlamps
to boost the vehicle system voltage
to properly charge the battery.Four-Wire Harness Adapter
If towing a light-duty trailer with a
standard four-way, at pin
connector, an adapter is available
from your dealer/retailer.
Hold the adapter with the tab
pointing up.Connect the adapter to the
seven-pin universal heavy-duty
trailer connector attached to
the bracket on the hitch platform.
The ip cap on the vehicle’s harness
locks onto the tab and helps hold
the adapter in place. Plug the
four-way pin connector onto the
adapter.
4-52 Driving Your Vehicle

Trailer Brake Control Wiring
Harness
The trailer brake control wiring
harness is located under the
instrument panel to the right of the
steering column. The wires are
taped to the harness that goes to
the courtesy light under the
instrument panel. The harness has
the following wires:
Red Wire: AUX B+
Black Wire: Ground
Light Blue Wire: Brake Signal
Dark Blue Wire: Trailer Brakes
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 gure 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 seeTowing a
Trailer on page 4-42.
Driving Your Vehicle 4-53

Automatic Transmission
Fluid
When to Check and Change
Automatic Transmission Fluid
A good time to check the automatic
transmission uid level is when
the engine oil is changed.
Change the uid and lter at the
intervals listed inAdditional
Required Services on page 6-6, and
be sure to use the transmission
uid listed inRecommended Fluids
and Lubricants on page 6-12.
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 adding it yourself, be sure to follow
all the instructions here, or there
could be 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).Get the vehicle warmed up by
driving about 15 miles (24 km) when
outside temperatures are above
50°F (10°C). If it is colder than
50°F (10°C), drive the vehicle
in 3 (Third) until the engine
temperature gage moves and then
remains steady for 10 minutes.
A cold uid check can be made after
the vehicle has been sitting for
eight hours or more with the engine
off, but this is used only as a
reference. Let the engine run at
idle for ve minutes if outside
temperatures are 50°F (10°C) or
more. If it is colder than 50°F (10°C),
the engine might have to idle
longer. Should the uid level
be low during this cold check,
check the uid hot before adding
uid. Checking the uid hot gives
a more accurate reading of the
uid level.
5-18 Service and Appearance Care

If No Steam Is Coming From
The Engine Compartment
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. See “Driving
on Grades” underTowing a
Trailer on page 4-42.
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.
Engine Fan Noise
This 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 clutch is not
engaged. This improves fuel
economy and reduces fan noise.
Under heavy vehicle loading,
trailer towing and/or high outside
temperatures, the fan speed
increases when the clutch 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 disengages.
5-28 Service and Appearance Care

Fuse Usage
11 Not Used
12Transfer Case Control
Module
13 Radio
14 Body Control Module
15Rear Wiper Motor
(H3 Only)
16Rear Wiper Pump
Switch (H3 Only)
17Air Injection Reactor
(AIR) Pump Relay/
Transmission Control
Module (TCM)
(V8 Only)
18 Rear Vision Camera
19 Cluster
20Rear Turn Lamp,
Hazard Lamp
21Powertrain Control
Module 1
22Mass Air Flow Sensor,
Canister Vent Purge
SolenoidFuse Usage
23 Injector/V8 Coil
24 Fog Lamp
25Powertrain Control
Module B
26Transmission Control
Module (TCM)
27 Airbags
28 Not Used
29Antilock Brakes,
StabiliTrak
®
30 Rear Window Defogger
31 Canister Vent
32Regulated Voltage
Control Sensor
33 Ignition 1 (V8 Only)
34 Transmission
35Cruise Control,
Miscellaneous
36 Horn
37Driver Side Rear
Park Lamp
Fuse Usage
38 Amplier
39Daytime Running
Lamps
40Passenger Side
Headlamp
41 Driver Side Headlamp
42 Trailer Back-Up Lamp
43 Front Park Lamps
44Air Injection Reactor
(AIR) Solenoid
45Auxiliary Power 2/
Cigarette Lighter
46Electronic Throttle
Control
47 Oxygen Sensor
48 Air Conditioning Clutch
49 Rear Park Lamp
50 Stop Lamp
51Auxiliary Power 1/
Cigarette Lighter
52StabiliTrak
®, Antilock
Brakes
5-94 Service and Appearance Care

Fuse Usage
53Power Heated Seat,
Belt Switch
54Fuel System Control
Module (FSCM)
55 Trailer Parking Lamps
56Front Turn Signal,
Hazard Signal/
Courtesy Mirror
57 Power Sunroof
58Transfer Case Control
Module Switch
59Climate Control,
Control Head
60 Back-Up Lamp
61 Power Seats
62 AIR Pump
63Passenger Side
Power Window
64Antilock Brakes,
StabiliTrak
®2 Solenoid
67Antilock Brakes,
StabiliTrak
®1 Motor
Fuse Usage
68Driver Side Power
Window
82 Climate Control Fan
83Electronic Brake
Controller
84 Trailer B+ Fuse
85 Starter
91 Generator Megafuse
Relay Usage
66 Stop Lamp (H3T Only)
69 Fog Lamp
70High, Low Beam
Headlamps
71 Rear Defogger
72Windshield Wiper
On/Off
73Windshield Wiper
High/Low
74 Horn
75 Headlamp
Relay Usage
76 Air Conditioning Clutch
77Powertrain Control
Module (Starter)
78 Run, Crank
79Daytime Running
Lamps
80Air Injection Reactor
(AIR) Solenoid
81 Powertrain
86 Back Up Lamps
87Ignition 3 Heating,
Ventilation,
Air Conditioning
88Retained Accessory
Power/Accessory
89 Park Lamp
Diode Usage
65 Wiper Diode
90Air Conditioning Clutch
Diode
Service and Appearance Care 5-95