2008 GMC YUKON engine

Running the Engine While Parked
It is better not to park with the engine running. But if you
ever have to, here are some things to know.
{CAUTION:
Idling the engine with the climate control
system off could allow dangerous exhaust into
your vehicle. See the earlier caution under
Engine Exhaust on page 2-47.
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the climate control fan is at the highest setting.
One place this can happen is a garage.
Exhaust — with CO — can come in easily.
NEVER park in a garage with the engine
running.
Another closed-in place can be a blizzard. See
Winter Driving on page 4-30.
{CAUTION:
It can be dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P) with
the parking brake rmly set. Your vehicle can
roll. Do not leave your vehicle when the engine
is running unless you have to. If you have left
the engine running, the vehicle can move
suddenly. You or others could be injured. To
be sure your vehicle will not move, even when
you are on fairly level ground, always set the
parking brake and move the shift lever to
PARK (P).
2-48

Instrument Panel Overview...............................3-4
Hazard Warning Flashers................................3-6
Other Warning Devices...................................3-6
Horn.............................................................3-6
Tilt Wheel.....................................................3-6
Turn Signal/Multifunction Lever.........................3-7
Turn and Lane-Change Signals........................3-8
Headlamp High/Low-Beam Changer..................3-9
Flash-to-Pass.................................................3-9
Windshield Wipers..........................................3-9
Rainsense™ II Wipers...................................3-10
Windshield Washer.......................................3-11
Rear Window Wiper/Washer...........................3-12
Cruise Control..............................................3-13
Exterior Lamps.............................................3-16
Headlamps on Reminder................................3-17
Daytime Running Lamps (DRL).......................3-17
Automatic Headlamp System..........................3-18
Fog Lamps..................................................3-19
Auxiliary Roof Mounted Lamp.........................3-19
Instrument Panel Brightness...........................3-20
Dome Lamps...............................................3-20
Dome Lamp Override....................................3-20
Entry Lighting...............................................3-20
Exit Lighting.................................................3-20
Reading Lamps............................................3-21
Electric Power Management...........................3-21Battery Run-Down Protection..........................3-22
Accessory Power Outlet(s).............................3-22
Ashtray(s) and Cigarette Lighter......................3-23
Climate Controls............................................3-23
Climate Control System.................................3-23
Dual Automatic Climate Control System...........3-26
Outlet Adjustment........................................
.3-33
Rear Air Conditioning and Heating System.......3-33
Rear Air Conditioning and Heating System
and Electronic Climate Controls...................3-35
Warning Lights, Gages, and Indicators............3-37
Instrument Panel Cluster................................3-38
Speedometer and Odometer...........................3-39
Trip Odometer..............................................3-39
Tachometer.................................................3-39
Safety Belt Reminders...................................3-39
Airbag Readiness Light..................................3-40
Passenger Airbag Status Indicator...................3-41
Charging System Light..................................3-43
Voltmeter Gage............................................3-44
Brake System Warning Light..........................3-44
Antilock Brake System
Warning Light...........................................3-46
StabiliTrak
®Indicator Light..............................3-46
Engine Coolant Temperature Gage..................3-47
Tire Pressure Light.......................................3-47
Section 3 Instrument Panel
3-1

Reading Lamps
If your vehicle has reading lamps they are located on
the overhead console.
To turn on the reading lamps, press the button located
next to each lamp. To turn them off, press the button
again.
Your vehicle may also have reading lamps in other
locations. To turn the lamps on or off, press the button
located next to the lamp.
The lamps are xed and cannot be adjusted.
Electric Power Management
The vehicle has Electric Power Management (EPM) that
estimates the battery’s temperature and state of
charge. It then adjusts the voltage for best performance
and extended life of the battery.
When the battery’s state of charge is low, the voltage is
raised slightly to quickly put the charge back in. When
the state of charge is high, the voltage is lowered slightly
to prevent overcharging. If the vehicle has a voltmeter
gage or a voltage display on the Driver Information
Center (DIC), you may see the voltage move up
or down. This is normal. If there is a problem, an alert
will be displayed.The battery can be discharged at idle if the electrical
loads are very high. This is true for all vehicles. This is
because the generator (alternator) may not be
spinning fast enough at idle to produce all the power
that is needed for very high electrical loads.
A high electrical load occurs when several of the
following loads are on: headlamps, high beams, fog
lamps, rear window defogger, climate control fan at high
speed, heated seats, engine cooling fans, trailer
loads, and loads plugged into accessory power outlets.
EPM works to prevent excessive discharge of the
battery. It does this by balancing the generator’s output
and the vehicle’s electrical needs. It can increase
engine idle speed to generate more power, whenever
needed. It can temporarily reduce the power demands of
some accessories.
Normally, these actions occur in steps or levels, without
being noticeable. In rare cases at the highest levels
of corrective action, this action may be noticeable to the
driver. If so, a Driver Information Center (DIC)
message might be displayed, such as Battery Saver
Active or Service Battery Charging System. If this
message is displayed, it is recommended that the driver
reduce the electrical loads as much as possible. See
DIC Warnings and Messages on page 3-64.
3-21

6(Floor):This mode directs most of the air to the
oor outlets, with some of the air directed to the
windshield, side window outlets, and second row oor
outlets. In this mode, the system will automatically select
outside air. Recirculation cannot be selected when in
Floor Mode.
The right knob can also be used to select defog or
defrost mode. For more information, see “Defogging and
Defrosting” later in this section.
By positioning the right knob between two modes, a
combination of those two modes is selected.
The air conditioning compressor will be on unless the
outside temperature is close to freezing.
9(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the fan speed.
Turn the knob all the way counterclockwise to turn the
front system off.
?(Recirculation):Press this button to turn the
recirculation mode on. When the button is pressed, an
indicator light will come on.This mode keeps outside air from entering the vehicle.
It can be used to reduce outside air and prevent
odors from entering the vehicle. Recirculation may also
help cool the air inside the vehicle more quickly once
the temperature inside the vehicle is less than the
outside temperature.
The recirculation mode cannot be used with oor,
defrost, or defogging modes. If you try to select
recirculation in one of those modes, the indicator will
ash three times and turn off. The air conditioning
compressor will also come on when this mode is
activated. While in recirculation mode the windows may
fog when the weather is cold and damp. To clear the
fog, select either the defog or defrost mode and increase
the fan speed. Recirculation mode can be turned off
by pressing the button again, or turning off the engine.
AUX (Auxiliary):Pressing this button will turn the
rear heating and air conditioning on. SeeRear
Air Conditioning and Heating System on page 3-33or
Rear Air Conditioning and Heating System and
Electronic Climate Controls on page 3-35for more
information.
3-24

Temperature Control:Rotate the thumbwheels up or
down to increase or decrease the temperature on
the driver’s side or the passenger side of the vehicle for
the dual zone system, if equipped. Otherwise, turn
the center knob clockwise or counterclockwise to
increase or decrease the temperature inside the vehicle.
#(Air Conditioning):Press this button on the left
knob to turn the air conditioning system on or off. When
A/C is pressed, an indicator light comes on to show
that the air conditioning has been activated.
On hot days, open the windows to let hot inside air
escape; then close them. This helps to reduce the time
it takes for your vehicle to cool down. It also helps
the system to operate more efficiently.
The air conditioning system removes moisture from the
air, so a small amount of water might drip underneath
the vehicle while idling or after turning off the engine.
This is normal.
Defogging and Defrosting
Fog on the inside of the windows is a result of high
humidity (moisture) condensing on the cool window
glass. This can be minimized if the climate control
system is used properly. There are two modes to clear
fog or frost from your windshield. Turn the right knob
clockwise to select the defog or defrost mode.
-(Defog):The defog mode is used to clear the
windows of fog or moisture and warm the passengers.
This mode directs air to the windshield, oor outlets,
and side window vents. When this mode is selected, the
system turns off recirculation and runs the air
conditioning compressor unless the outside temperature
is close to freezing. The recirculation mode cannot be
selected while in the defog mode. Do not drive the
vehicle until all the windows are clear.
0(Defrost):The defrost mode is used to remove fog
or frost from the windshield more quickly. This mode
directs a portion of the air to the windshield and
side window vents and some to the oor vents. In this
mode, the system will automatically force outside air into
the vehicle. The recirculation mode cannot be selected
while in the defrost mode. The air conditioning
compressor will run automatically in this setting, unless
the outside temperature is close to freezing. Do not
drive the vehicle until all the windows are clear.
3-25

Rear Window Defogger
The rear window defogger uses a warming grid to
remove fog from the rear window.
<(Rear Window Defogger):Press this button on
the right knob to turn on the rear window defogger. The
system will automatically turn off several minutes
after it has been activated. The defogger can also be
turned off by pressing the button again or by turning off
the engine. Do not drive the vehicle until all the
windows are clear.
If your vehicle has heated outside rearview mirrors, the
mirrors will heat to help clear fog or frost from the
surface of the mirror when the rear window defog button
is pressed.
Notice:Do not use anything sharp on the inside of
the rear window. If you do, you could cut or
damage the warming grid, and the repairs would not
be covered by your warranty. Do not attach a
temporary vehicle license, tape, a decal or anything
similar to the defogger grid.
Dual Automatic Climate Control
System
The heating, cooling, and ventilation in your vehicle
can be controlled with this system. Your vehicle also has
a ow-through ventilation system described later in
this section.
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Different climate control settings can be selected for the
driver and passengers.
3-26

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 the vehicle. The light on the
button will illuminate 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. Use the driver’s or
passenger’s temperature buttons 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 load and
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.
O(On/Off):Press this button to turn off the 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. Recirculation
can be selected once vent or bi-level mode has
been selected. The temperature can also be adjusted
using either temperature button. If the air delivery mode
or temperature settings are adjusted with the system
off, the display will illuminate briey to show you
the settings and then return off. Press the on/off button
or the up down arrows on the fan switch, the defrost
button, AUTO button, or the air conditioning button
to turn the system on when it is off.
3-28

@(Recirculation):Press this button to turn the
recirculation mode on. When the button is pressed, an
indicator light comes on.
This mode keeps outside air from entering the vehicle.
It can be used to reduce outside air and prevent
odors from entering the vehicle. Recirculation may also
help cool the air inside the vehicle more quickly once
the temperature inside the vehicle is less than the
outside temperature.
The recirculation mode cannot be used with oor,
defrost, or defogging modes. If you try to select
recirculation in one of those modes, the indicator will
ash three times and turn off. The air conditioning
compressor will also come on when this mode is
activated. While in recirculation mode the windows may
fog when the weather is cold and damp. To clear the
fog, select either the defog or defrost mode and increase
the fan speed. Recirculation mode can be turned off
by pressing the button again, or turning off the engine.Air Conditioning
#
(Air Conditioning):Press this button to turn the
air conditioning (A/C) compressor on and off. When
air conditioning is selected, an indicator light comes on
to show that the air conditioning has been activated.
Pressing this button when the outside temperature is too
cool for air conditioning will make the air conditioning
indicator ash three times and then turn off to show that
the air conditioning mode is not available. If the air
conditioning is on and the outside temperature drops
below a temperature which is too cool for air
conditioning to be effective, the air conditioning light will
turn off to show that the air conditioning mode has
been canceled.
On hot days, open the windows long enough to let hot
inside air escape. This helps to reduce the time it
takes for your vehicle to cool down. It also helps the
system to operate more efficiently.
The air conditioning system removes moisture from the
air, so a small amount of water might drip underneath
the vehicle while idling or after turning off the engine.
This is normal.
3-30