cooling GMC SIERRA CLASSIC 2007 Owners Manual

Tow/Haul Mode
If your vehicle has an automatic transmission, it
may have a Tow/Haul mode. If your vehicle has an
Allison Transmission
®see “Tow/Haul Mode
(Allison Transmission®) following. Tow/Haul mode
adjusts the transmission shift pattern to reduce
shift cycling, providing increased performance,
vehicle control, and transmission cooling
when towing or hauling heavy loads.The selector button is located on the end of the
shift lever. Turn the Tow/Haul on and off by
pressing the button. When the Tow/Haul is on, a
light on the instrument panel cluster will come on.
SeeTow/Haul Mode Light on page 264for
more information.
If your vehicle has the Performance
Package-Enhanced Towing, activating the manual
selectable ride will adjust the shock absorber
characteristics to enhance the ride and handling of
the vehicle for towing or hauling heavy loads.
Also see Tow Haul Mode underTowing a Trailer
on page 429for more information.
147

Tow/Haul Mode (Allison
Transmission®)
If your vehicle has an Allison Transmission®,it
may have a Tow/Haul mode. Tow/Haul mode
adjusts the transmission shift pattern to reduce
shift cycling, providing increased performance,
vehicle control, and transmission cooling
when towing or hauling heavy loads.The selector button is located on the end of the shift
lever. Turn the Tow/Haul on and off by pressing the
button. When the Tow/Haul is on, a light on the
instrument panel cluster will come on.
SeeTow/Haul Mode Light on page 264for more
information.
Also see “Tow Haul Mode” underTowing a Trailer
on page 429for more information.
Grade Braking and Cruise Grade
Braking (Allison Transmission®)
Grade Braking and Cruise Grade Braking assists
when driving on a downhill grade. It maintains
the vehicle’s speed by automatically using a shift
schedule that uses the engine and the
transmission to slow the vehicle. This reduces
wear on the brakes system and increases control
of the vehicle. The system constantly monitors
the vehicle’s speed, acceleration, engine torque,
and brake pedal usage. It detects when the
truck is on a downhill grade and the driver’s desire
to slow down by pressing the brake.
148

W(Defog):Airow is delivered through the oor
outlets, the windshield defroster outlets, and
the side window defroster outlets. The air ow can
be divided between oor and defrost depending
upon where the knob is placed between the
settings.
1(Defrost):This setting directs most air
through the windshield defroster outlets, side
window defroster outlets, and some through the
oor outlets.
Dual Climate Control System
With this system you can control the heating,
cooling, and ventilation for your vehicle.
Fan Control
9(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the fan
speed. Turn the knob to the off position to turn
off the fan. If the knob is in off, outside air will still
enter the vehicle and will be directed based on
the position of the mode knob. The temperature
can also be adjusted using the temperature levers.
Turn the right knob clockwise or counterclockwise
to direct the airow inside of your vehicle.
231

Dual Automatic Climate Control
System
With this system, you can control the heating,
cooling, and ventilation in your vehicle. Your
vehicle also has a ow-through ventilation system
described later in this section.
You can select different climate control settings for
the driver and passengers.
Driver’s Side Temperature Knob
The driver’s side knob is used to adjust the
temperature of the air coming through the system
on the driver’s side. The temperature can be
adjusted even if the system is turned off. This is
possible since outside air will always ow through
the system as the vehicle is moving forward
unless it is set to recirculation mode. See
“Recirculation” later in this section.
Turn the knob counterclockwise or clockwise to
lower or increase the cabin temperature. The
display will show the temperature setting
decreasing or increasing and an arrow pointing to
the driver will be displayed under and to the
left of the temperature setting.
235

When AUTO is selected, the air conditioning
operation and air inlet will be automatically
controlled. The air conditioning compressor will
run when the outside temperature is over
about 40°F (4°C). The air inlet will normally be
set to outside air. If it is hot outside, the air
inlet may automatically switch to recirculate
inside air to help quickly cool down your
vehicle. The light on the button will come on in
recirculation.
2. Set the driver’s and passenger’s temperature.
To nd your comfort setting, start with a 74°F
(23°C) temperature setting and allow about
20 minutes for the system to regulate. Turn the
driver’s or passenger’s side temperature
knob to adjust the temperature setting as
necessary. If you choose the temperature
setting of 60°F (15°C) the system will remain
at the maximum cooling setting. If you
choose the temperature setting of 90°F (32°C)
the system will remain at the maximum
heat setting. Choosing either maximum setting
will not cause the vehicle to heat or cool
any faster.Be careful not to cover the solar sensor
located on the top of the instrument panel
near the windshield. This sensor regulates air
temperature based on sun intensity. It also
turns on the headlamps. For more information
on the solar sensor, see “Sensors” later in
this section.
To avoid blowing cold air in cold weather, the
system will delay turning on the fan until
warm air is available. The length of delay
depends on the engine coolant temperature.
Pressing the fan switch will override this delay
and change the fan to a selected speed.
9(Off):Press this button to turn off the entire
climate control system. Outside air will still
enter the vehicle, and will be directed to the oor.
This direction can be changed by pressing the
mode button. The temperature can also be
adjusted using either temperature knob. Press the
up or down arrows on the fan switch, the defrost
button, the AUTO button, or the air conditioning
button to turn the system on when it is off.
237

The ABS warning light should come on briey
when you turn the ignition key to RUN. If the light
does not come on then, have it xed so it will
be ready to warn you if there is a problem.
Traction Off Light
If your vehicle has the
Traction Assist System,
this light should
come on briey when
you turn the ignition
to RUN.
If the light does not come on then, the system
may require service. Have it xed so it will be there
to warn you if the system is turned off.
If the light stays on, or comes on when you are
driving, there may be a problem with your Traction
Assist System and your vehicle may need
service. When this light is on, the system will not
limit wheel spin. Adjust your driving accordingly.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your
vehicle is working. During a majority of the
operation, the gage will read 210°F (100°C) or
less. If you are pulling a load or going up hills, it is
normal for the temperature to uctuate and
approach the 250°F (122°C) mark. If the gage
reaches the 260°F (125°C) mark, it indicates that
the cooling system is working beyond its
capacity.
SeeEngine Overheating on page 505.
United StatesCanada
256

DRIVER DOOR AJAR
If the driver’s door is not fully closed, this message
will appear on the display and you will hear a
chime. Stop and turn off the vehicle, check
the door for obstructions, and close the door again.
Check to see if the message still appears on the
DIC. Pressing any of the four DIC buttons will
acknowledge the message and clear it from the
DIC display. If your vehicle does not have the four
DIC buttons, pressing the trip odometer reset
stem will acknowledge the message and clear it
from the DIC display.
ENGINE COOLANT HOT
If the cooling system temperature gets hot, this
message will appear in the DIC. Turn off the
air conditioning. If the message is still on, or if the
engine coolant temperature gage continues to
rise, pull the vehicle over when it is safe to do so.
SeeEngine Coolant Temperature Gage on
page 256for more information. Stop the vehicle
and let the engine idle in PARK (P) for a few
minutes, or NEUTRAL with the parking brake set
for manual transmissions, to allow the coolant
to reach a safe temperature. This message
will clear when the coolant temperature drops to
safe operating temperature.
ENGINE OVERHEATED
Notice:If you drive your vehicle while the
engine is overheating, severe engine damage
may occur. If an overheat warning appears
on the instrument panel cluster and/or
DIC, stop the vehicle as soon as possible.
Do not increase the engine speed above
normal idling speed. SeeEngine Overheating
on page 505for more information.
If the engine cooling system reaches unsafe
temperatures for operation, this message
will appear in the DIC and you will hear a chime.
Stop and turn off the vehicle as soon as it is
safe to do so to avoid severe damage. This
message will clear when the engine has cooled to
a safe operating temperature.
273

If your vehicle has a low coolant level sensor, this
message will appear on the DIC if the engine
coolant level is low. Adding coolant to the coolant
recovery tank will clear the message. See
Cooling System on page 508. Pressing any of the
four DIC buttons will acknowledge the message
and clear it from the DIC display. If your
vehicle does not have the four DIC buttons,
pressing the trip odometer reset stem will
acknowledge the message and clear it from the
DIC display.
OIL LIFE RESET
This message will appear on the display for about
10 seconds after resetting the change engine
oil message. See “Engine Oil Life System” under
DIC Operation and Displays on page 266and
Engine Oil (Gasoline Engine) on page 486
for more information.
OIL PRESSURE LOW
Notice:If you drive your vehicle while the
engine oil pressure is low, severe engine
damage may occur. If a low oil pressure
warning appears on the Driver Information
Center (DIC), stop the vehicle as soon as
possible. Do not drive the vehicle until the
cause of the low oil pressure is corrected. See
Engine Oil (Gasoline Engine) on page 486
for more information.
If low oil pressure levels occur, this message will
be displayed on the DIC and a chime will
sound. Stop the vehicle as soon as safely possible
and do not operate it until the cause of the low
oil pressure has been corrected. Check the oil as
soon as possible and have your vehicle serviced
by your dealer. SeeEngine Oil (Gasoline Engine)
on page 486.
275

PASSENGER DOOR AJAR
If the passenger’s door is not fully closed, this
message will appear on the display and you will
hear a chime. Stop and turn off the vehicle, check
the door for obstructions, and close the door
again. Check to see if the message still appears
on the DIC. Pressing any of the four DIC
buttons will acknowledge the message and clear it
from the DIC display. If your vehicle does not
have the four DIC buttons, pressing the trip
odometer reset stem will acknowledge the
message and clear it from the DIC display.
RANGE SHIFT INHIBITED
(Allison Transmission®Only)
If the transmission is unable to shift into a selected
gear, this message will appear on the DIC. The
electronic shift position indicator on the instrument
panel cluster may blink when this occurs. To
make the vehicle shift to the requested gear, you
may have to shift back to PARK (P) or
NEUTRAL (N) and re-select the desired gear.
REDUCED ENGINE POWER
This message is displayed when the cooling
system temperature gets too hot and the engine
further enters the engine coolant protection mode.
SeeEngine Overheating on page 505for further
information.
This message will also display when the vehicle’s
engine power is reduced. Reduced engine
power can affect the vehicle’s ability to accelerate.
If this message is on, but there is no reduction
in performance, proceed to your destination. The
performance may be reduced the next time
the vehicle is driven. The vehicle may be driven at
a reduced speed while this message is on, but
acceleration and speed may be reduced. Anytime
this message stays on, the vehicle should be
taken to your dealer for service as soon as
possible.
276

After Off-Road Driving
Remove any brush or debris that has collected
on the underbody, chassis, or under the hood.
These accumulations can be a re hazard.
After operation in mud or sand, have the brake
linings cleaned and checked. These substances
can cause glazing and uneven braking. Check the
body structure, steering, suspension, wheels,
tires, and exhaust system for damage. Also, check
the fuel lines and cooling system for any leakage.
Your vehicle will require more frequent service
due to off-road use. Refer to the Maintenance
Schedule for additional information.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to
be impaired — by alcohol or drugs, with night
vision problems, or by fatigue.
Here are some tips on night driving.
Drive defensively.
Do not drink and drive.
Adjust the inside rearview mirror to reduce the
glare from headlamps behind you.
Since you cannot see as well, you may need
to slow down and keep more space between
you and other vehicles.
Slow down, especially on higher speed roads.
Your vehicle’s headlamps can light up only so
much road ahead.
In remote areas, watch for animals.
If you are tired, pull off the road in a safe
place and rest.
No one can see as well at night as in the daytime.
But as we get older these differences increase.
A 50-year-old driver may require at least twice as
much light to see the same thing at night as a
20-year-old.
What you do in the daytime can also affect your
night vision. For example, if you spend the
day in bright sunshine you are wise to wear
sunglasses. Your eyes will have less trouble
adjusting to night. But if you are driving, do not
wear sunglasses at night. They may cut down on
glare from headlamps, but they also make a
lot of things invisible.
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