2007 HUMMER H3 tow

Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. See the Maintenance
Schedule for more on this. Things that are
especially important in trailer operation are
automatic transmission uid, engine oil, axle
lubricant, belts, 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
Light-Duty Trailer Wiring Package
If your vehicle is not equipped with 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
If you want to add on a trailer tow, it should be
installed by your dealer or a qualied service
center. Also, seeAdd-On Electrical Equipment
on page 416for more information.
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Heavy-Duty Trailer Wiring Package
If your vehicle is equipped with 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.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 you are charging a remote (non-vehicle) battery,
turn on the headlamps to boost the vehicle
system voltage to properly charge the battery.
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Four-Wire Harness Adapter
If you need to tow a light-duty trailer with a
standard four-way, at pin connector, an adapter
is available from your dealer.
Use this adapter to
connect a standard
four-way pin connector
to the seven-wire
harness on your vehicle.
Connect the adapter with the tab pointing up.
The ip cap on the vehicle’s seven-wire harness
will lock onto the tab (see arrow in the previous
graphic) and help hold the adapter in place.
Plug the four-way pin connector onto the adapter.
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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 will contain
the following wires:
Red Wire: AUX B+
Black Wire: Ground
Light Blue Wire: Brake Signal
Dark Blue Wire: Trailer Brakes
Trailer Recommendations
You must subtract your hitch loads from the
Cargo Weight Rating (CWR). CWR is the
maximum weight of the load your vehicle can
carry. It doesn’t include the weight of the people
inside, but you can gure about 150 lbs. (68 kg)
for each seat. The total cargo load must not
be more than your vehicles CWR.
Weigh your vehicle with your 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 297.
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A. Windshield Washer Fluid Reservoir. See
“Adding Washer Fluid” underWindshield
Washer Fluid on page 346.
B. Engine Coolant Recovery Tank. SeeEngine
Coolant on page 335.
C. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 328.
D. Power Steering Fluid Reservoir. SeePower
Steering Fluid on page 345.
E. Automatic Transmission Fluid Dipstick (If
Equipped). See “Checking the Fluid Level” under
Automatic Transmission Fluid on page 329.
F. Engine Oil Fill Cap. See “When to Add Engine
Oil” underEngine Oil on page 323.
G. Radiator Pressure Cap. SeeCooling System
on page 340.
H. Remote Negative (−) Terminal (GND). See
Jump Starting on page 352.
I. Engine Oil Dipstick. See “Checking Engine Oil”
underEngine Oil on page 323.
J. Positive (+) Battery Terminal. SeeJump
Starting on page 352.
K. Brake Fluid Reservoir. See “Brake Fluid” under
Brakes on page 347.L. Engine Compartment Fuse Block. SeeEngine
Compartment Fuse Block on page 418.
M. Battery. SeeBattery on page 351.
N. Hydraulic Clutch Fluid Reservoir (If Equipped).
SeeHydraulic Clutch on page 334.
Engine Oil
Checking Engine Oil
It is a good idea to check the engine oil every time
you get fuel. In order to get an accurate reading,
the oil must be warm and the vehicle must be
on level ground.
The engine oil dipstick handle is a yellow loop.
SeeEngine Compartment Overview on page 322
for the location of the engine oil dipstick.
1. Turn off the engine and give the oil several
minutes to drain back into the oil pan. If you
do not do this, the oil dipstick might not
show the actual level.
2. Pull out the dipstick and clean it with a paper
towel or cloth, then push it back in all the
way. Remove it again, keeping the tip down,
and check the level.
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3. With your foot on the brake pedal, move the
shift lever through each gear range, pausing
for about three seconds in each range.
Then, position the shift lever in PARK (P).
4. Let the engine run at idle for three minutes
or more.
Then, without shutting off the engine, follow
these steps:
1. Flip the handle up and then pull out the
dipstick and wipe it with a clean rag or
paper towel.
The automatic
transmission dipstick
handle with this symbol
on it is located in the
engine compartment on
the passenger’s side
of the vehicle.
SeeEngine Compartment Overview on
page 322for more information on location.
2. Push it back in all the way, wait three seconds
and then pull it back out again.3. Check both sides of the dipstick, and read the
lower level. The uid level must be in the
COLD area, below the cross-hatched area, for
a cold check or in the HOT or cross-hatched
area for a hot check. Be sure to keep the
dipstick pointed down to get an accurate
reading.
4. If the uid level is in the acceptable range,
push the dipstick back in all the way; then
ip the handle down to lock the dipstick
in place.
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Checking Coolant
The coolant recovery
tank cap has this
symbol on it.
It is located toward the rear of the engine
compartment on the passenger’s side of the
vehicle. SeeEngine Compartment Overview on
page 322for more information on location.
The vehicle must be on a level surface. When
your engine is cold, the coolant level should be
at FULL COLD, or a little higher. When your
engine is warm, the level could be above the
FULL COLD level.
Adding Coolant
If you need more coolant, add the proper
DEX-COOL®coolant mixture at the coolant
recovery tank.
{CAUTION:
Turning the radiator pressure cap when
the engine and radiator are hot can allow
steam and scalding liquids to blow out
and burn you badly. With the coolant
recovery tank, you will almost never
have to add coolant at the radiator. Never
turn the radiator pressure cap — even
a little — when the engine and radiator
are hot.
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CAUTION: (Continued)
You or others could be badly burned.
Stop your engine if it overheats, and get
out of the vehicle until the engine is cool.
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.
If No Steam Is Coming From Your
Engine
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. See “Driving on Grades” under
Towing a Trailer on page 297.If you get the overheat warning with no sign of
steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in
NEUTRAL while stopped. If it is safe to do so,
pull off the road, shift to PARK (P) or
NEUTRAL and let the engine idle.
2. Turn off the air conditioning.
3. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
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.
If the warning continues, pull over, stop, and park
your vehicle right away.
If there is still no sign of steam, idle the engine for
three minutes while you are parked. Push down
the accelerator until the engine speed is about
twice as fast as normal idle speed for at least three
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.
You may decide not to lift the hood but to get
service help right away.
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