index GMC SUBURBAN 1999 Owner's Guide

2-24
AUTO 4WD: This setting is ideal for use when road
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 2HI.
4HI: Use 4HI 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.
4LO: This setting also engages your front axle and
delivers extra torque. You may never need 4LO. It sends
maximum power to all four wheels. You might choose
4LO if you are driving off
-road in deep sand, deep mud,
deep snow and 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. See ªParking Brakeº in the Index.
NEUTRAL: Shift the vehicle's transfer case to NEUTRAL
only when towing your vehicle. See ªRecreational Vehicle
Towingº or ªTowing Your Vehicleº in the Index for
more information.
Indicator lights in the switches show which setting you are
in. The indicator lights will come on briefly 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 flash while shifting the
transfer case. It will remain illuminated 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.

2-25
If the SERVICE 4WD light stays on, you should take
your vehicle to your dealer for service. See ªService
4WDº in the Index for further information.
Shifting to 4HI or AUTO 4WD
Press and release the 4HI or AUTO 4WD switch. This can
be done at any speed (except when shifting from 4LO),
and the indicator light will flash while shifting. It will
remain illuminated when the shift is completed.
Shifting to 2HI
Press and release the 2HI switch. This can be done at
any speed (except when shifting from 4LO).
Shifting to 4LO
To shift to 4LO, the ignition must be in RUN and the
vehicle must be stopped or moving less than 3 mph
(4.8 km/h) with the transmission in NEUTRAL (N).
The preferred method for shifting into 4LO is to have
your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h).
Press and release the 4LO switch. You must wait for
the 4LO indicator light to stop flashing and remain
illuminated before shifting your transmission in gear.If the 4LO switch is pressed when your vehicle is in
gear and/or moving, the 4LO indicator light will flash
for 30 seconds and not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N). After 30 seconds the
transfer case will return to the setting last chosen.
Shifting Out of 4LO
To shift from 4LO to 4HI, AUTO 4WD or 2HI your
vehicle must be stopped or moving less than 3 mph
(4.8 km/h) with the transmission in NEUTRAL (N) and
the ignition in RUN. The preferred method for shifting
out of 4LO is to have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Press and release the 4HI, AUTO
4WD or 2HI switch. You must wait for the 4HI, AUTO
4WD or 2HI indicator light to stop flashing and remain
illuminated before shifting your transmission into gear.
If the 4HI, AUTO 4WD or 2HI switch is pressed
when your vehicle is in gear and/or moving, the 4HI,
AUTO 4WD or 2HI indicator light will flash for
30 seconds but will not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N).

2-27
Parking Brake
To set the parking brake, hold the regular brake pedal
down with your right foot. Push down the parking brake
pedal with your left foot.
If the ignition is on, the brake system warning light will
flash. A chime will activate when the parking brake is
applied and the vehicle is moving at least 3 mph (5 km/h)
for at least three seconds.
To release the parking brake, hold the regular brake
pedal down. Pull the bottom edge of the lever, located
above the parking brake pedal, marked BRAKE
RELEASE, to release the parking brake.
If the ignition is on when the parking brake is released,
the brake system warning light will go off.
NOTICE:
Driving with the parking brake on can cause
your rear brakes to overheat. You may have to
replace them, and you could also damage other
parts of your vehicle.
If you are towing a trailer and are parking on any hill,
see ªTowing a Trailerº in the Index. That section shows
what to do first to keep the trailer from moving.

2-28
Shifting Into PARK (P)
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 firmly set. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. To be sure your vehicle won't move, even
when you're on fairly level ground, use the steps
that follow. With four
-wheel drive if your
transfer case is in NEUTRAL (N), your vehicle
will be free to roll, even if your shift lever is in
PARK (P). So, be sure the transfer case is in a
drive gear
-- not in NEUTRAL (N). If you're
pulling a trailer, see ªTowing a Trailerº in
the Index.
1. Hold the brake pedal down with your right foot and
set the parking brake.
2. Move the shift lever into PARK (P) position like this:

Pull the shift lever toward you.

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If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P) and the
parking brake is firmly set before you leave it. After you
move the shift lever into PARK (P), hold the regular
brake pedal down. Then, see if you can move the shift
lever away from PARK (P) without first pulling it
toward you. If you can, it means that the shift lever
wasn't fully locked into PARK (P).
Torque Lock
If you are parking on a hill and you don't shift your
transmission into PARK (P) properly, the weight of the
vehicle may put too much force on the parking pawl in
the transmission. You may find it difficult to pull the
shift lever out of PARK (P). This is called ªtorque lock.º
To prevent torque lock, set the parking brake and then
shift into PARK (P) properly before you leave the
driver's seat. To find out how, see ªShifting Into
PARK (P)º in the Index.
When you are ready to drive, move the shift lever out
of PARK (P) before you release the parking brake.
If torque lock does occur, you may need to have another
vehicle push yours a little uphill to take some of the
pressure from the parking pawl in the transmission,
so you can pull the shift lever out of PARK (P).
Shifting Out of PARK (P)
Your vehicle has an automatic transmission shift lock
control system. You have to fully apply your regular
brakes before you can shift from PARK (P) when the
ignition is in RUN. See ªAutomatic Transmissionº in
the Index.
If you cannot shift out of PARK (P), ease pressure on
the shift lever and push the shift lever all the way up
into PARK (P) as you maintain brake application.
Then, move the shift lever into the gear you want.
If you ever hold the brake pedal down but still can't
shift out of PARK (P), try this:
1. Turn the key to the OFF ignition position.
2. Apply and hold the brake until the end of Step 4.
3. Shift the vehicle to NEUTRAL (N).
4. Start the vehicle and then shift to the drive gear
you want.
5. Have the system fixed as soon as you can.

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Running Your Engine While
You're Parked
It's better not to park with the engine running. But if
ever you 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
ªEngine Exhaustº).
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the fan switch 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 ªBlizzardº in the Index.)
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 firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. If you've left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure your
vehicle won't move, even when you're on fairly
level ground, always set your parking brake and
move the shift lever to PARK (P).
Four-wheel drive vehicles with the transfer case
in NEUTRAL (N) will allow the vehicle to roll,
even if your shift lever is in PARK (P). So, be
sure the transfer case is in a drive gear
-- not in
NEUTRAL (N). Always set your parking brake.
Follow the proper steps to be sure your vehicle won't
move. See ªShifting Into PARK (P)º in the Index.
If you're pulling a trailer, see ªTowing a Trailerº in
the Index.

2-34 Autoride
(If Equipped)
The Autoride
feature will provide a superior vehicle
ride and handling under a variety of passenger and
loading conditions.
The system is fully automatic and uses a computer
controller to continuously monitor vehicle speed, wheel
to body position, lift/dive and steering position of the
vehicle. The controller then sends signals to each shock
absorber to independently adjust the damping level to
provide the optimum vehicle ride.
Autoride also interacts with the Tow/Haul switch that,
when engaged, will provide additional control of the
shock absorbers. This additional control results in better
ride and handling characteristics when the vehicle is
loaded or towing a trailer. See ªTow/Haul Modeº in
the Index for more information.
Locking Rear Axle
If your vehicle has this feature, your locking rear axle
can give you additional traction on snow, mud, ice, sand
or gravel. It works like a standard axle most of the time,
but when one of the rear wheels has no traction and the
other does, this feature will allow the wheel with
traction to move the vehicle.
Windows
Manual Windows
Turn the hand crank on each door to raise or lower
manual windows.
Power Windows (If Equipped)
If you have the optional power windows, the controls
are located on each of the side doors.

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The driver's door has a switch for the passenger
windows as well. Your power windows will work when
the ignition has been turned to ACCESSORY or RUN
or when Retained Accessory Power (RAP) is present.
See ªRetained Accessory Powerº in the Index.
Press the rear of the switch with the power window
symbol on it to lower the window or the front to raise it.
The driver's window also has an express down feature
that allows the window to be lowered without holding
the switch. Press and hold the rear of the window switch
for one second to activate the express down mode.
The express down mode can be canceled at any time
by pressing the opposite side of the switch. To open the
window partway, lightly tap the switch until the window
is at the desired position.
If you have power windows, the power window switch has
a lockout feature. This feature prevents the rear windows
from operating except from the driver's position when the
front driver's side button labeled WINDOW LOCK is
engaged. When the button is not engaged, the rear power
windows will operate again.Horn
To sound the horn, press the center pad on the
steering wheel.
Tilt Wheel (If Equipped)
The tilt steering wheel
allows you to adjust the
steering wheel before
you drive.
You can also raise it to the highest level to give your
legs more room when you enter and exit the vehicle.
To tilt the wheel, hold the steering wheel and pull the
lever located on the lower left of the column. Move the
steering wheel to a comfortable level, then release the
lever to lock the wheel in place.

2-37
If a bulb is burned out, replace it to help avoid an
accident. If the arrows don't go on at all when you
signal a turn, check for burned
-out bulbs and a blown
fuse (see ªFuses and Circuit Breakersº in the Index).
Turn Signal On Chime
If your turn signal is left on for more than 3/4 of a mile
(1.2 km), a chime will sound at each flash of the turn
signal. To turn off the chime, move the turn signal lever
to the off position.
Headlamp High/Low Beam Changer
To change the headlamps from low to high beam or high
to low beam, pull the multifunction lever all the way
toward you. Then release it.
When the high beams
are on, this light on the
instrument panel also
will be on.
Flash-To-Pass Feature
This feature allows you to use your high-beam
headlamps to signal a driver in front of you that you
want to pass. It works even if your headlamps are off.
To use it, pull the turn signal lever toward you, but not
so far that you hear it click.
If your headlamps are off or on low
-beam, your
high
-beam headlamps will turn on. They'll stay on
as long as you hold the lever toward you and the
high
-beam indicator on the instrument panel will
come on. Release the lever to turn the high
-beam
headlamps off.

2-46
The fog lamps will go off whenever your high-beam
headlamps come on. When the high beams go off, the
fog lamps will come on again.
The fog lamps will be cancelled after the ignition is
turned off. If you still want to use the fog lamps after
you restart the vehicle, you will need to press the fog
lamp switch again.
Auxiliary Roof Mounted Lamp Switch
(If Equipped)
This switch includes wiring
provisions for a dealer or a
qualified service center to
install an auxiliary roof
lamp. This switch is located
on the center of the
instrument panel near
the comfort controls.
When the switch wiring is connected to an auxiliary roof
mounted lamp, pressing the button will activate the lamp
and illuminate an indicator light near the button. Pressing
the button again will turn off the roof mounted lamp.If your vehicle has this switch, your vehicle may have
the Snow Plow Prep Package. For further information
see ªSnow Plow Prep Packageº in the Index.
Interior Lamps
Instrument Panel Intensity Control
The instrument panel intensity control is located to the
right of the headlamp switch.
Rotate the thumbwheel up to increase the intensity of
the instrument panel lights. To turn on the dome lamps,
with the vehicle doors closed, rotate the thumbwheel all
the way up. Rotate the thumbwheel down to decrease
the intensity of the lights.
Exit Lighting
With exit lighting, the interior lamps will come on when
you remove the key from the ignition. The lights will
not come on if the DOME OVERRIDE button is
pressed in.
Illuminated Entry
Your vehicle is equipped with an illuminated entry feature.
When the doors are opened, the dome lamps will come
on if the DOME OVERRIDE button is in the ªoutº
position. If the DOME OVERRIDE button is pressed in,
the lamps will not come on.