ac system GMC YUKON 2005 Service Manual

Liftgate Glass and Liftgate
To open a mechanical lock system from the outside,
insert the key into the lock and turn it counterclockwise
to unlock the glass and liftgate.
The liftgate glass can be opened using the button on
the liftgate after the doors have been unlocked. This can
be done by using either the power door locks or the
remote keyless entry system.
To open the entire liftgate, lift the handle located in the
center of the door.
To lock a power lock system from the outside, insert the
key into the lock button and turn clockwise. All doors will
lock. You may also use the keyless entry system or the
power door locks to lock the liftgate and liftgate glass.
Windows
{CAUTION:
Leaving children, helpless adults, or pets in a
vehicle with the windows closed is dangerous.
They can be overcome by the extreme heat
and suffer permanent injuries or even death
from heat stroke. Never leave a child, a
helpless adult, or a pet alone in a vehicle,
especially with the windows closed in warm or
hot weather.
2-14

Theft-Deterrent Systems
Vehicle theft is big business, especially in some cities.
Although your vehicle has a number of theft-deterrent
features, we know that nothing we put on it can make it
impossible to steal.
Content Theft-Deterrent
Your vehicle may be equipped with a content
theft-deterrent alarm system.
The security light, located
on the instrument panel
cluster, will ash as
you open the door, while
the ignition is off, to
indicate the system is
being activated.This message reminds you to activate the theft-deterrent
system. Here is how to do it:
1. Open the door.
2. Lock the door with the power door lock switch or
the remote keyless entry transmitter. The security
light should come on and ash. If using the
remote keyless entry transmitter, the door does not
need to be open.
If the delayed locking feature is active, the alarm
will not be activated until all doors are closed
and the security light goes off.
3. Close all doors. The security light will stop ashing
and go off after approximately 30 seconds. The
content theft deterrent alarm is not armed until the
security light goes off.
If a door is opened without using the key or the remote
keyless entry transmitter, the alarm will go off. Your
vehicle’s headlamps will ash and the horn will sound for
about two minutes, then will turn off to save the
battery power.
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The theft-deterrent system will not activate if you lock
the doors with a key or use the manual door lock.
It activates only if you use a power door lock switch with
the door open, or with the remote keyless entry
transmitter. You should also remember that you can
start your vehicle with the correct ignition key if the alarm
has been set off.
Here is how to avoid setting off the alarm by accident:
If you do not want to activate the theft-deterrent
system, the vehicle should be locked with the
door key after the doors are closed.
Always unlock a door with a key, or use the remote
keyless entry transmitter. Unlocking a door any
other way will set off the alarm if the system
has been armed.
If you set off the alarm by accident, unlock any door
with the key. You can also turn off the alarm by pressing
unlock on the remote keyless entry transmitter or by
placing the key in the ignition and turning it to start.
Testing the Alarm
The alarm can be tested by following these steps:
1. From inside the vehicle, lower the driver’s window
and open the driver’s door.
2. Activate the system by locking the doors with the
power door lock switch while the door is open, or
with the remote keyless entry transmitter.
3. Get out of the vehicle, close the door and wait for
the security light to go out.
4. Then reach in through the window, unlock the door
with the manual door lock and open the door. This
should set off the alarm.
If the alarm does not sound when it should, but the
vehicle’s headlamps ash, check to see if the horn
works. The horn fuse may be blown. To replace the
fuse, seeFuses and Circuit Breakers on page 5-105.
If the alarm does not sound or the vehicle’s headlamps
do not ash, see your dealer for service.
2-18

Passlock®
Your vehicle is equipped with the
Passlock®theft-deterrent system.
Passlock
®is a passive theft-deterrent system.
Passlock®enables fuel if the ignition lock cylinder is
turned with a valid key. If a correct key is not used or the
ignition lock cylinder is tampered with, fuel is disabled.
If the engine stalls and the security light ashes,
wait until the light stops ashing before trying to restart
the engine. Remember to release the key from
START as soon as the engine starts.
If the engine is running and the security light comes on,
you will be able to restart the engine if you turn the
engine off. However, your Passlock
®system is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by Passlock
®at this
time. You may also want to check the fuse. See
Fuses and Circuit Breakers on page 5-105. See your
dealer for service.
In an emergency, call the GM Roadside Assistance
Center. SeeRoadside Assistance Program on page 7-5.
Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an elaborate
break-in. But it will perform better in the long run if
you follow these guidelines:
Keep your speed at 55 mph (88 km/h) or less for
the rst 500 miles (805 km).
Do not drive at any one speed, fast or slow, for
the rst 500 miles (805 km). Do not make
full-throttle starts.
Avoid making hard stops for the rst 200 miles
(322 km) or so. During this time your new
brake linings are not yet broken in. Hard stops
with new linings can mean premature wear
and earlier replacement. Follow this breaking-in
guideline every time you get new brake
linings.
Do not tow a trailer during break-in. SeeTowing
a Trailer on page 4-67for more information.
2-19

Ignition Positions
Use the key to turn the ignition switch to four different
positions.
A (LOCK):This position locks the ignition and
transmission. It is a theft-deterrent feature. You will only
be able to remove the key when the ignition is turned
to LOCK.
Notice:Using a tool to force the key from the
ignition switch could cause damage or break the
key. Use the correct key and turn the key only with
your hand. Make sure the key is all the way in. Ifit is, turn the steering wheel left and right while you
turn the key hard. If none of this works, then
your vehicle needs service.
B (ACCESSORY):This position lets you use things
like the radio and the windshield wipers when the engine
is off.
Notice:Lengthy operation of features such as the
radio in the accessory ignition position may drain the
battery and prevent your vehicle from starting. Do not
operate your vehicle in the accessory ignition
position for a long period of time.
C (RUN):This is the position for driving.
D (START):This position starts the engine.Retained Accessory Power (RAP)
Your vehicle may be equipped with a Retained
Accessory Power (RAP) feature which will allow certain
features on your vehicle to continue to work up to
10 minutes after the ignition key is turned to OFF.
Your radio, power windows, sunroof (if equipped), and
OnStar
®System (if equipped) will work when the ignition
key is in RUN or ACCESSORY. Once the key is
turned from RUN to LOCK, these features will continue
to work for up to 10 minutes or until a door is opened.
2-20

Starting the Engine
Your vehicle is equipped with Starter Motor Control. This
feature assists in starting the engine and protects the
electrical system. This feature may cause the engine to
crank even after the ignition key is not in START.
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine will not start in any other position — that is
a safety feature. To restart when you are already
moving, use NEUTRAL (N) only.
Notice:Do not try to shift to PARK (P) if your
vehicle is moving. If you do, you could damage the
transmission. Shift to PARK (P) only when your
vehicle is stopped.
1. With your foot off the accelerator pedal, turn the
ignition key to START. When the engine starts,
let go of the key. The idle speed will go down as
your engine gets warm.
Notice:Holding your key in START for longer than
15 seconds at a time will disengage the starter
motor, cause your battery to be drained much
sooner, and add excessive heat that can damage
your starter motor. Try not to hold the key in START
for longer than 15 seconds and wait about
15 seconds between each try to help avoid draining
your battery or damaging your starter.2. If it does not start within 10 seconds, push the
accelerator pedal all the way to the oor, while you
hold the ignition key in START. When the engine
starts, let go of the key and let up on the accelerator
pedal. Wait about 15 seconds between each try.
When starting your engine in very cold weather (below
0°F or−18°C), do this:
1. With your foot off the accelerator pedal, turn the
ignition key to START and hold it there up to
15 seconds. When the engine starts, let go
of the key.
2. If your engine still will not start, or starts but then
stops, it could be ooded with too much gasoline.
Try pushing your accelerator pedal all the way to the
oor and holding it there as you hold the key in
START for about three seconds. When the engine
starts, let go of the key and accelerator. If the
vehicle starts briey but then stops again, do the
same thing, but this time keep the pedal down
for ve or six seconds. This clears the extra
gasoline from the engine.
Notice:Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way the
engine operates. Before adding electrical equipment,
check with your dealer. If you do not, your engine
might not perform properly.
2-21

Automatic Transfer Case
For four-wheel drive vehicles with StabiliTrak®, see
StabiliTrak®System on page 4-10.
Use these buttons to shift into and out of four-wheel
drive.
You can choose among four driving settings:
AUTO 4WD (Automatic Four-Wheel Drive):This
setting is ideal for use when road surface traction
conditions are variable. When driving your vehicle in
AUTO 4WD, the front axle is engaged, but the vehicle’s
power is sent only to the rear wheels. When the
vehicle senses a loss of traction, the system will
automatically engage four-wheel drive. Driving in this
mode results in slightly lower fuel economy than
Two-Wheel High.
2
m(Two Wheel-High):This setting is used for
driving in most street and highway situations. Your front
axle is not engaged in two-wheel drive. This setting
also provides the best fuel economy.
4
m(Four Wheel-High):Use the four-wheel high
position when you need extra traction, such as on snowy
or icy roads or in most off-road situations. This setting
also engages your front axle to help drive your vehicle.
This is the best setting to use when plowing snow.4
n(Four Wheel-Low):This setting also engages
your front axle and delivers extra torque. You may never
need this setting. It sends maximum power to all four
wheels. You might choose Four Wheel-Low if you
are driving off-road in deep sand, deep mud, deep snow,
and while climbing or descending steep hills.
StabiliTrak
®will not engage in this mode. See
StabiliTrak®System on page 4-10for more information.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. SeeParking Brake on
page 2-35.
NEUTRAL (N):Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-62orTowing
Your Vehicle on page 4-62for more information.
2-28

Shifting Out of NEUTRAL
To shift out of NEUTRAL do the following:
1. Set the parking brake and apply the regular brake
pedal.
2. Shift the transmission to NEUTRAL (N) and turn the
ignition to RUN with the engine off.
3. Press the button for the desired transfer case shift
position (Two-Wheel High, Four-Wheel High, AUTO
4WD, or Four-Wheel Low).
4. After the transfer case has shifted out of NEUTRAL
the NEUTRAL light will go out.
5. Release the parking brake.
6. Start the engine and shift the transmission to the
desired position.
Excessively shifting the transfer case into or out of the
different modes may cause the transfer case to
enter the shift protection mode. This will protect the
transfer case from possible damage and will only
allow the transfer case to respond to one shift per
10 seconds. The transfer case may stay in this
mode for up to three minutes.
All-Wheel Drive with StabiliTrak®
If your vehicle has this system, you will see the buttons
shown below. With this system, engine power is sent
to all four wheels when you select the AWD button.
The transfer case buttons
are located to the left of
the instrument panel
cluster. Use these buttons
to shift between the
various modes of
four-wheel drive.
All-wheel drive is like four-wheel drive, but there is
no separate lever or switch to engage or disengage
the front axle. It is fully automatic, and when combined
with StabiliTrak
®, the all-wheel drive system adjusts
itself as needed for road conditions.
2-31

The three modes you can choose between are:
d(StabiliTrak®):This button is used to enable or
disable the StabiliTrak®and is also used to shift the
transfer case into Neutral (N). For more information on
using StabiliTrak
®, seeStabiliTrak®System on
page 4-10.
f(All-Wheel Drive):This button allows the transfer
case to distribute power to all four wheels as needed
depending on road and driving conditions.
4
n(4LO):This button allows the transfer case to
deliver extra torque to the wheels, and provides for
precise control of wheel speed by engine braking. You
may never need this setting. It sends maximum power to
all four wheels. You might choose four-wheel low if you
are driving off-road in deep sand, deep mud, deep snow,
and while climbing or descending steep hills.
{CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P). You or someone
else could be seriously injured. Be sure to set
the parking brake before placing the transfer
case in NEUTRAL. SeeParking Brake on
page 2-35.
N (Neutral):Shift the vehicle’s transfer case to
NEUTRAL only when towing your vehicle. See
Recreational Vehicle Towing on page 4-62orTowing
Your Vehicle on page 4-62for more information.
Indicator lights in the buttons show which mode you are
in. The indicator lights will come on briey when you
turn on the ignition and one will stay on. If the lights do
not come on, you should take your vehicle to your
dealer for service. An indicator light will ash while the
transfer case is shifting. It will remain on when the
shift is complete. If for some reason the transfer case
cannot make a requested shift, it will return to the
last chosen setting.
2-32

If the SERVICE 4WD message stays on, you should
take your vehicle to your dealer for service. See
SERVICE 4WD underDriver Information Center (DIC)
on page 3-54.
Shifting Into Four Wheel Low
To shift to the Four-Wheel Low position, the ignition
must be in RUN and the vehicle must be stopped
or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N). Press and release the
Four-Wheel Low switch. You must wait for the
Four-Wheel Low indicator light to stop ashing and
remain on before shifting your transmission in gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
ashing could damage the transfer case. To
help avoid damaging your vehicle, always wait for
the Four-Wheel Low indicator light to stop ashing
before shifting the transmission into gear.
If the Four-Wheel Low button is pressed when your
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light will ash for 30 seconds and not complete
the shift unless your vehicle is moving less than
3 mph (5 km/h) and the transmission is in NEUTRAL (N).
After 30 seconds, the transfer case will return to the
setting last chosen.
When in Four-Wheel Low, StabiliTrak
®is automatically
disabled. For more information seeStabiliTrak®
System on page 4-10.
Shifting Out of Four Wheel-Low
To shift from Four-Wheel Low to All-Wheel Drive, your
vehicle must be stopped or moving less than 3 mph
(5 km/h) with the transmission in NEUTRAL (N) and the
ignition in RUN. Press and release the all-wheel drive
button. You must wait for the All-Wheel Drive indicator
light to stop ashing and remain illuminated before
shifting your transmission into gear.
If the All-Wheel Drive button is pressed when your
vehicle is in gear and/or moving, the All-Wheel Drive
indicator light will ash for 30 seconds but will not
complete the shift unless your vehicle is moving less
than 3 mph (5 km/h) and the transmission is in
NEUTRAL (N).
Shifting Into NEUTRAL
To shift the transfer case to NEUTRAL, do the following:
1. Make sure the vehicle is parked so that it will
not roll.
2. Set the parking brake. SeeParking Brake on
page 2-35for more information.
3. Start the vehicle or turn the ignition to RUN.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to All-Wheel Drive.
2-33