2010 HUMMER H3 light

Driving and Operating 9-81
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 figure about
68 kg (150 lbs) 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 seeTrailer
Towing on page 9‑74.
Conversions and
Add-Ons
Add-On Electrical
Equipment
Notice: Do not add anything
electrical to the vehicle unless
you check with your dealer first.
Some electrical equipment can
damage the vehicle and the
damage would not be covered
by the vehicle's warranty. Some
add-on electrical equipment can
keep other components from
working as they should.
Add-on equipment can drain the
vehicle battery, even if the vehicle is
not operating.
The vehicle has an airbag system.
Before attempting to add anything
electrical to the vehicle, see
Servicing the Airbag-Equipped
Vehicle
on page 3‑40and Adding
Equipment to the Airbag-Equipped
Vehicle on page 3‑40.

10-26 Vehicle Care
Brakes
This vehicle has disc brakes. Disc
brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{WARNING
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
an accident. When the brake
wear warning sound is heard,
have the vehicle serviced.
Notice: Continuing to drive with
worn-out brake pads could result
in costly brake repair. Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications in
Capacities and
Specifications on page 12‑2.
Brake linings should always be
replaced as complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service might be
required.
Brake Adjustment
Every time the brakes are applied,
with or without the vehicle moving,
the brakes adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is
complex. Its many parts have to be
of top quality and work well together
if the vehicle is to have really good
braking. The vehicle was designed
and tested with top-quality brake
parts. When parts of the braking
system are replaced, be sure to get
new, approved replacement parts.
If this is not done, the brakes might
not work properly. For example,
installing disc brake pads that are
wrong for the vehicle, can change
the balance between the front and
rear brakes —for the worse. The
braking performance expected can
change in many other ways if the
wrong replacement brake parts are
installed.

Vehicle Care 10-27
Brake Fluid
The brake master cylinder reservoir
is filled with DOT 3 brake fluid as
indicated on the reservoir cap. See
Engine Compartment Overview
on
page 10‑6for the location of the
reservoir. There are only two reasons why the
brake fluid level in the reservoir
might go down:
.The brake fluid level goes down
because of normal brake lining
wear. When new linings are
installed, the fluid level goes
back up.
.A fluid leak in the brake
hydraulic system can also cause
a low fluid level. Have the brake
hydraulic system fixed, since a
leak means that sooner or later
the brakes will not work well.
Do not top off the brake fluid.
Adding fluid does not correct a leak.
If fluid is added when the linings
are worn, there will be too much
fluid when new brake linings are
installed. Add or remove brake fluid,
as necessary, only when work is
done on the brake hydraulic system.
{WARNING
If too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged.
Add brake fluid only when work is
done on the brake hydraulic
system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning
Light on page 5‑14.

Vehicle Care 10-33
Headlamp Aiming
The vehicle may have a visual
optical headlamp aiming system.
The aim has been preset at the
factory and should need no further
adjustment.
However, if the vehicle is damaged
in a crash, the headlamp aim may
be affected and adjustment may be
necessary.
If oncoming vehicles flash their high
beams at you, this may also mean
the vertical aim needs to be
adjusted.
It is recommended that the vehicle
is taken to your dealer for service if
the headlamps need to be re-aimed.
It is possible however, to re-aim the
headlamps as described.The vehicle should be:.Placed so the headlamps are
7.6 m (25 ft) from a light colored
wall or other flat surface.
.On a level surface which is level
all the way to a wall.
.Placed so it is at a right angle to
the wall or other flat surface.
.Clear of any snow, ice, or mud
on it.
.Fully assembled, the tires
properly inflated, and all other
work stopped while headlamp
aiming is being performed.
.Normally loaded with the spare
tire in its original location and a
full tank of fuel and one person
or 75 kg (160 lbs) sitting on the
driver seat.To adjust the vertical aim:
1. Open the hood. See
Hood
on
page 10‑5.
2. Record the distance from the ground to the aim dot on the
headlamp.

10-34 Vehicle Care
3. At a wall, measure from theground upward the recorded
distance from Step 2 and
mark it.
4. Draw or tape a horizontal line the width of the vehicle at the
wall where it was marked it
Step 4.
Notice: Do not cover a headlamp
to improve beam cut-off when
aiming. Covering a headlamp may
cause excessive heat build-up
which may cause damage to the
headlamp. 5. Turn on the headlamps and
place a piece of cardboard
or equivalent in front of the
headlamp not being aimed. This
should allow only the beam of
light from the headlamp being
aimed to be seen on the wall.
Passenger Side Shown
6. Locate the vertical headlamp aiming screws, which are under
the hood near each headlamp
assembly.
The adjustment screw can be
turned with an E8 Torx
®socket
or T15 Torx®screwdriver.
7. Turn the vertical aiming screw
until the headlamp beam is
aimed to the horizontal tape
line. Turn it clockwise or
counterclockwise to raise or
lower the beam.
The top edge of the cut-off
should be positioned at the
bottom edge of the horizontal
tape line.
8. Repeat Steps 7 and 8 for the opposite headlamp.

Vehicle Care 10-39
Fuses and Circuit
Breakers
The wiring circuits in your vehicle
are protected from short circuits by
a combination of fuses and circuit
breakers. This greatly reduces the
chance of fires caused by electrical
problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.
If you ever have a problem on the
road and do not have a spare fuse,
you can borrow one that has the
same amperage. Just pick some
feature of your vehicle that you can
get along without—like the radio
or cigarette lighter —and use its
fuse, if it is the correct amperage.
Replace it as soon as you can.
Engine Compartment
Fuse Block
The engine compartment fuse
block is located on the driver side
of the engine compartment. See
Engine Compartment Overview
on
page 10‑6for more information on
location.
To remove the cover, push in on the
tabs at the ends of the cover and
lift. To reinstall the cover, line up the
tabs and push down on the cover
until the tabs clicks into place.
Notice: Spilling liquid on any
electrical components on the
vehicle may damage it. Always
keep the covers on any electrical
component.

10-42 Vehicle Care
FuseUsage
39 Daytime Running
Lamps
40 Passenger Side
Headlamp
41 Driver Side
Headlamp
42 Trailer
Back-Up Lamp
43 Front Park Lamps
44 Air Injection Reactor
(AIR) Solenoid
45 Auxiliary Power 2/
Cigarette Lighter
46 Electronic Throttle
Control
47 Oxygen Sensor
48 Air Conditioning
Clutch
49 Rear Park Lamp
50 Stop Lamp Fuse
Usage
51 Auxiliary Power 1/
Cigarette Lighter
52 StabiliTrak
®,
Antilock Brake
System
53 Power Heated Seat,
Belt Switch
54 Fuel System Control
Module (FSCM)
55 Trailer Parking
Lamps
56 Front Turn Signal,
Hazard Signal,
Courtesy Mirror
57 Power Sunroof
58 Transfer Case
Control Module
Switch
59 Climate Controls
Control Head
60 Back‐Up Lamp
61 Power Seats Fuse Usage
62 Air Injection Reactor
(AIR) Pump
63 Passenger Side
Power Window
64 Antilock Brake
System,
StabiliTrak
®2
Solenoid
67 Antilock Brake
System,
StabiliTrak
®1 Motor
68 Driver Side Power
Window
82 Climate Control Fan
83 Electronic Brake
Controller
84 Trailer B+ Fuse
85 Starter
91 Generator Megafuse

Vehicle Care 10-45
and service description. See the
“Tire Size”illustration later in this
section for more detail.
(B) TPC Spec (Tire
Performance Criteria
Specification)
:Original
equipment tires designed to
GM's specific tire performance
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet
or exceed all federal safety
guidelines.
(C) DOT (Department of
Transportation)
:The
Department of Transportation
(DOT) code indicates that
the tire is in compliance with
the U.S. Department of
Transportation Motor Vehicle
Safety Standards.
(D) Tire Identification Number
(TIN)
:The letters and numbers
following DOT code are the Tire
Identification Number (TIN). The TIN shows the
manufacturer and plant code,
tire size, and date the tire
was manufactured. The TIN is
molded onto both sides of the
tire, although only one side may
have the date of manufacture.
(E) Tire Ply Material
:The type
of cord and number of plies in
the sidewall and under the tread.
(F) Uniform Tire Quality
Grading (UTQG)
:Tire
manufacturers are required
to grade tires based on
three performance factors:
treadwear, traction, and
temperature resistance.
For more information, see
Uniform Tire Quality Grading
on
page 10‑61
.
(G) Maximum Cold Inflation
Load Limit
:Maximum load
that can be carried and the
maximum pressure needed
to support that load. For information on
recommended tire pressure
see
Tire Pressure
on page 10‑51
and Vehicle Load Limitson
page 9‑27
.
Light Truck (LT-Metric) Tire
(A) Tire Size:The tire size
code is a combination of letters
and numbers used to define a
particular tire's width, height,
aspect ratio, construction type,
and service description. See the
“Tire Size” illustration later in this
section for more detail.