2007 GMC YUKON light

Press this button at the end of the shift lever to
enable tow/haul mode.
When the button is pressed, a light on the
instrument panel will illuminate to indicate that
Tow/Haul has been selected. Tow/Haul may
be turned off by pressing the button again, at
which time the indicator light on the instrument
panel will turn off. The vehicle will automatically
turn off tow/haul every time it is started.Tow/Haul is designed to be most effective
when the vehicle and trailer combined weight
is at least 75 percent of the vehicle’s Gross
Combination Weight Rating (GCWR). See “Weight
of the Trailer” later in this section. Tow/Haul is
most useful under the following driving conditions:
When pulling a heavy trailer or a large or
heavy load through rolling terrain.
When pulling a heavy trailer or a large or
heavy load in stop and go traffic.
When pulling a heavy trailer or a large or
heavy load in busy parking lots where
improved low speed control of the vehicle is
desired.
Operating the vehicle in Tow/Haul when lightly
loaded or with no trailer at all will not cause
damage. However, there is no benet to the
selection of Tow/Haul when the vehicle is
unloaded. Such a selection when unloaded may
result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a
heavy trailer or a large or heavy load.
402

Trailer Wiring Harness
Heavy-Duty Trailer Wiring Package
Your vehicle is equipped with the seven-wire
trailer towing harness. This harness with a
seven-pin universal heavy-duty trailer connector is
attached to the rear bumper beam. It is located
next to the integrated trailer hitch.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 w/ Black Stripe: Battery Feed*
Dark Blue: Trailer Brake*
*The fuses for these two circuits are installed in
the underhood electrical center, but the circuits are
not connected. They should be installed by your
dealer or a qualied service center.
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.
414

Electric Brake Control Wiring
Provisions
These wiring provisions are included with your
vehicle as part of the heavy-duty trailer wiring
package. These provisions are for an electric
brake controller. The red/black stripe power feed
will not be connected to the battery until the
ring terminal is unstowed and connected to the
underhood electrical center. 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.
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 400.
415

{CAUTION:
If you spill fuel and then something ignites
it, you could be badly burned. Fuel can
spray out on you if you open the fuel cap
too quickly. This spray can happen if your
tank is nearly full, and is more likely in hot
weather. Open the fuel cap slowly and wait
for any hiss noise to stop. Then unscrew
the cap all the way.
Be careful not to spill fuel. Do not top off or overll
the tank and wait a few seconds after you have
nished pumping before removing the nozzle.
Clean fuel from painted surfaces as soon as
possible. SeeWashing Your Vehicle on page 530.
When replacing the fuel cap, turn it clockwise until
it clicks. Make sure the cap is fully installed. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. This would
allow fuel to evaporate into the atmosphere.
SeeMalfunction Indicator Lamp on page 237.If your vehicle has a Driver Information Center
(DIC), the TIGHTEN GAS CAP message will be
displayed if the fuel cap is not properly installed.
{CAUTION:
If a re starts while you are refueling,
do not remove the nozzle. Shut off the
ow of fuel by shutting off the pump or
by notifying the station attendant. Leave
the area immediately.
Notice:If you need a new fuel cap, be sure to
get the right type. Your dealer can get one
for you. If you get the wrong type, it may not
t properly. This may cause your malfunction
indicator lamp to light and may damage
your fuel tank and emissions system. See
Malfunction Indicator Lamp on page 237.
427

When to Inspect the Engine
Air Cleaner/Filter
If your vehicle has an air lter restriction indicator,
it lets you know when the engine air cleaner/lter
needs to be replaced. On vehicles with a restriction
indicator, you should inspect the air lter
restriction indicator at every oil change and
replace the engine air cleaner/lter when the
indicator tells you to.
On vehicles without an air lter restriction indicator,
inspect the air cleaner/lter at the MaintenanceII
intervals and replace it at the rst oil change
after each 50,000 mile (83 000 km) interval.
SeeScheduled Maintenance on page 551for
more information. If you are driving in dusty/dirty
conditions, inspect the lter at each engine oil
change.
How to Inspect the Engine
Air Cleaner/Filter
Vehicles With an Air Filter Restriction
Indicator
Locate the air lter restriction indicator on the
engine air cleaner/lter cover. When the indicator
turns black or is in the red/orange “change”
zone, replace the lter and reset the indicator.
See the steps following to replace the engine
air cleaner/lter and to reset the air lter restriction
indicator.
Vehicles Without an Air Filter Restriction
Indicator
To inspect the air cleaner/lter, remove the engine
air cleaner/lter from the vehicle by following
step 1 through 6. When you have the engine air
cleaner/lter removed, lightly shake it to release
loose dust and dirt. If the engine air cleaner/lter
remains caked with dirt, a new lter is required.
438

Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is
designed to remain in your vehicle for ve years or
150,000 miles (240 000 km), whichever occurs
rst, if you add only DEX-COOL
®extended
life coolant.
The following explains your cooling system and
how to add coolant when it is low. If you have
a problem with engine overheating, seeEngine
Overheating on page 448.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Give freezing protection down to
−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as
they should.Notice:Using coolant other than DEX-COOL
®
may cause premature engine, heater core,
or radiator corrosion. In addition, the engine
coolant may require changing sooner, at
the rst maintenance service after each
30,000 miles (50 000 km) or 24 months,
whichever occurs rst. Any repairs would not
be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your
vehicle.
445

Brakes
Brake Fluid
Your brake master
cylinder reservoir is
lled with DOT-3 brake
uid. SeeEngine
Compartment Overview
on page 430for the
location of the reservoir.
There are only two reasons why the brake uid
level in the reservoir might go down. The rst
is that the brake uid goes down to an acceptable
level during normal brake lining wear. When
new linings are put in, the uid level goes back
up. The other reason is that uid is leaking out of
the brake system. If it is, you should have your
brake system xed, since a leak means that
sooner or later your brakes will not work well,
or will not work at all.So, it is not a good idea to top off your brake uid.
Adding brake uid will not correct a leak. If you
add uid when your linings are worn, then you will
have too much uid when you get new brake
linings. You should add or remove brake uid,
as necessary, only when work is done on
the brake hydraulic system.
{CAUTION:
If you have too much brake uid, it can spill
on the engine. The uid will burn if the
engine is hot enough. You or others could
be burned, and your vehicle could be
damaged. Add brake uid only when work
is done on the brake hydraulic system.
See “Checking Brake Fluid” in this section.
When the brake uid falls to a low level, the brake
warning light will come on. SeeBrake System
Warning Light on page 233.
Refer to the Maintenance Schedule to determine
when to check your brake uid. SeeScheduled
Maintenance on page 551.
459

Notice:
Using the wrong uid can badly damage
brake system parts. For example, just a
few drops of mineral-based oil, such
as engine oil, in your brake system can
damage brake system parts so badly that
they will have to be replaced. Do not
let someone put in the wrong kind of uid.
If you spill brake uid on your vehicle’s
painted surfaces, the paint nish can
be damaged. Be careful not to spill brake
uid on your vehicle. If you do, wash it
off immediately. SeeWashing Your Vehicle
on page 530.
Brake Wear
Your vehicle has four-wheel 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 may come and go or be heard all
the time your vehicle is moving, except when you
are pushing on the brake pedal rmly.
{CAUTION:
The brake wear warning sound means that
soon your brakes will not work well. That
could lead to an accident. When you hear
the brake wear warning sound, have your
vehicle serviced.
Notice:Continuing to drive with worn-out
brake pads could result in costly brake repair.
Some driving conditions or climates may cause
a brake squeal when the brakes are rst applied or
lightly applied. This does not mean something is
wrong with your brakes.
461