2007 HUMMER H3 trailer

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.
308

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.
309

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.
310

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).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 THIRD (3) 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), you may have to idle the engine
longer. Should the uid level be low during this cold
check, you must check the uid hot before adding
uid. Checking the uid hot will give you a more
accurate reading of the uid level.
Checking the Fluid Level
Prepare your vehicle as follows:
1. Park your vehicle on a level place. Keep the
engine running.
2. With the parking brake applied, place the shift
lever in PARK (P).
330

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.
339

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.
Power Steering Fluid
SeeEngine
Compartment Overview
on page 322for
reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power
steering uid unless you suspect there is a leak
in the system or you hear an unusual noise.
A uid loss in this system could indicate a problem.
Have the system inspected and repaired.
345

Fuse Usage
9 Sunroof, Front Washer Pump
10 Accessories (SPO)
11 Air Compressor
12 Transfer Case Control Module
13Radio, Heating, Ventilation,
Air Conditioning Display
14 Body Control Module
15 Rear Wiper Motor
16 Rear Wiper Pump Switch
17 Air Injection Reactor (AIR) Solenoid
18 Spare 6
19 Cluster
20 Rear Turn Signal, Hazard Signal
21 Powertrain Control Module 1
22Mass Air Flow Sensor,
Purge Solenoid
23 Injector
24 Fog Lamp
25 Powertrain Control Module B
26 Spare 4
27 Airbags
28 Back-up Lamps
29 Anti-lock Brakes, StabiliTrak
®
30 Rear Window Defogger
Fuse Usage
31 Canister Vent
32 Regulated Voltage Control VSense+
33 Ignition 1
34 Transmission
35 Cruise, Inside Rearview Mirror
36 Horn
37 Driver’s Side Rear Park Lamp
38 Amplier
39Reduced Intensity Low-Beam
Daytime Running Lamps
40 Passenger’s Side Headlamp
41 Driver’s Side Headlamp
42 Trailer Back-Up Lamp
43 Front Park Lamps
44 Air Injection Reactor (AIR) Solenoid
45 Auxiliary Power 2
46 Electronic Throttle Control
47 Oxygen Sensor
48 Air Conditioning Clutch
49 Passenger’s Side Rear Park Lamp
50 XM™ Satellite Radio
51 Auxiliary Power 1
52 StabiliTrak
®, Anti-lock Brakes
53 Power Heater Switch
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Fuse Usage
54 Stop
55 Trailer Parking Lamps
56 Front Turn Signal, Hazard Signal
57 Power Sunroof
58Transfer Case Control Module
Switch
59 Climate Control
60 Spare 8
61 Power Seats
62 Air Pump
63 Passenger’s Side Power Window
64Anti-lock Brakes, StabiliTrak
®2
Solenoid
67Anti-lock Brakes, StabiliTrak
®1
Motor
68 Driver’s Side Power Window
82 Climate Control Fan
83 Electronic Brake Controller
84 Trailer B+ Fuse
85 Starter
91 Megafuse
Relay Usage
66 Fuel Pump
69 Fog Lamp
70 High, Low Beam Headlamps
71 Rear Defogger
72 Windshield Wiper On/Off
73 Windshield Wiper High/Low
74 Horn
75 Headlamp
76 Air Conditioning Clutch
77 Powertrain Control Module
78 Run, Crank
79Reduced Intensity Low-Beam
Daytime Running Lamps
80 Air Injection Reactor (AIR) Solenoid
81 Powertrain (Starter)
86 Spare 2
87 Heating, Ventilation, Air Conditioning
88 Retained Accessory Power
89 Park Lamp
Diode Usage
65 Wiper Diode
90 Air Conditioning Clutch Diode
421