1999 GMC SUBURBAN lock

2-15
OFF (C): This position lets you turn off the engine but
still turn the steering wheel. It doesn't lock the steering
wheel like LOCK. Use OFF if you must have your
vehicle in motion while the engine is off (for example,
if your vehicle is being pushed).
RUN (D): This is the position for driving.
START (E): This position starts your engine.
NOTICE:
If your key seems stuck in LOCK and you can't
turn it, be sure you are using the correct key;
if so, is it all the way in? If it is, then turn the
steering wheel left and right while you turn the
key hard. But turn the key only with your hand.
Using a tool to force it could break the key or the
ignition switch. If none of this works, then your
vehicle needs service.
Retained Accessory Power (If Equipped)
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 20 minutes after the ignition key is turned to OFF.
Your radio, power windows and overhead console will
work when the ignition key is in RUN or ACCESSORY.
Once the key is turned from RUN to OFF, these features
will continue to work for up to 20 minutes or until a
door is opened.
Starting Your Engine
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine won't start in any other position
-- that's a
safety feature. To restart when you're already moving,
use NEUTRAL (N) only.
NOTICE:
Don't 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.

2-18
CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the wrong
kind of extension cord could overheat and cause
a fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't reach,
use a heavy
-duty three-prong extension cord
rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and store
the cord as it was before to keep it away from moving
engine parts. If you don't, it could be damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead of
trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for
that particular area.
Automatic Transmission Operation
There are several different positions for your shift lever.
Your vehicle is equipped with an automatic transmission
and features an electronic shift position indicator within
the instrument panel cluster. This display must be
powered anytime the shift lever is capable of being
moved out of PARK (P). This means that if your key is
in OFF, rather than LOCK, there will be a small current
drain on your battery which could discharge your battery
over a period of time. If you have to leave your key in
the ignition in OFF for an extended period, it is
recommended that you remove the IGN 0 fuse from the
instrument panel fuse block. See ªFuses and Circuit
Breakersº in the Index.

2-19
PARK (P): This locks your rear wheels. It's the best
position to use when you start your engine because your
vehicle can't move easily.
CAUTION:
It is 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 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, always set your parking brake and
move the shift lever to PARK (P).
CAUTION: (Continued)
CAUTION: (Continued)
If you have four-wheel drive, your vehicle
will be free to roll
-- even if your shift lever
is in PARK (P)
-- if your transfer case is in
NEUTRAL (N). So, be sure the transfer case is in
a drive gear, two
-wheel high (2H) or four-wheel
high (4H) or four
-wheel low (4L) -- not in
NEUTRAL (N). See ªShifting Into PARK (P)º in
the Index. If you're pulling a trailer, see ªTowing
a Trailerº in the Index.
REVERSE (R): Use this gear to back up.
NOTICE:
Shifting to REVERSE (R) while your vehicle is
moving forward could damage your transmission.
Shift to REVERSE (R) only after your vehicle
is stopped.

2-22 Tow/Haul Mode Selector Switch
Your vehicle is equipped with a tow/haul mode. The
selector switch is located on the end of the column shift
lever. You can use this feature to assist when towing or
hauling a heavy load. See ªTow/Haul Modeº in the
Index for more information.
The Tow/Haul Mode also interacts with the Autoride

feature, if your vehicle is so equipped, to enhance the ride
when trailering or with a loaded vehicle. See ªAutoride
º
in the Index.
Four-Wheel Drive (If Equipped)
If your vehicle has four-wheel drive, you can send your
engine's driving power to all four wheels for extra
traction. To get the most satisfaction out of four
-wheel
drive, you must be familiar with its operation. Read the
part that follows before using four
-wheel drive. See the
appropriate text for the transfer case in your vehicle.
NOTICE:
Driving in the 4-WHEEL HIGH (4H) or
4
-WHEEL LOW (4L) positions for a long time
on dry or wet pavement could shorten the life
of your vehicle's drivetrain.
Front Axle Locking Feature
The front axle locks and unlocks automatically when
you shift the transfer case. Some delay for the axle to
lock or unlock is normal.

2-29

Move the lever up as far as it will go.
3. Be sure the transfer case is in a drive gear
-- not
in NEUTRAL (N).
4. Turn the ignition key to LOCK.
5. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is in PARK (P).
Leaving Your Vehicle With the
Engine Running
CAUTION:
It can be dangerous to leave your vehicle with the
engine running. Your vehicle could move
suddenly if the shift lever is not fully in PARK (P)
with the parking brake firmly set. If you have
four
-wheel drive and 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). And, if you leave the vehicle with
the engine running, it could overheat and even
catch fire. You or others could be injured. Don't
leave your vehicle with the engine running unless
you have to.

2-30
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.

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.