ignition GMC YUKON 1999 Owner's Guide

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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.
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, 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.Shifting to 4LO
To shift to 4LO, the vehicle's engine must be running 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 into 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 engine running. 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.

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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).
Shifting to Neutral
To shift the transfer case to neutral, first make sure the
vehicle is parked so that it will not roll:
1. Set the parking brake.
2. Start the vehicle.
3. Connect the vehicle to the towing vehicle.
4. Put the transmission in NEUTRAL (N).
5. Shift the transfer case to 2HI.
6. Simultaneously press and hold the 2HI and 4LO
buttons for 10 seconds. The red NEUTRAL light
will come on when the transfer case shift to neutral
is complete.7. Shift the transmission to REVERSE (R) for
one second, then shift to AUTOMATIC
OVERDRIVE
for one second.
8. Turn the ignition to OFF.
9. Place the transmission shift lever in PARK (P).
10. Release the parking brake prior to towing.
Shifting Out of Neutral
To shift out of neutral:
1. Set the parking brake and apply the regular brake
pedal.
2. Start the vehicle with the transmission in PARK (P).
3. Press the button for the desired transfer case shift
position (2HI, 4HI, AUTO 4WD or 4LO).
4. Put the transmission in NEUTRAL (N).
5. Shift the transmission lever to the desired position.
After the transfer case has shifted out of NEUTRAL,
the red light will go out.

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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
come on.
To release the parking
brake, hold the regular
brake pedal down. Pull the
lever, located just 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.

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Move the lever up as far as it will go.
3. Be sure the transfer case is in a drive gear
-- not
in NEUTRAL.
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. 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). 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.

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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 a brake-transmission shift interlock
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 brake
-transmission shift interlock system
fixed as soon as you can.

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Locking Rear Axle
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
Power Windows
The power window controls are located on each of the
side doors.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.
Push the rear of the switch with the power window
symbol on it to lower the window.
Push the front of the switch with the power window
symbol on it to raise the window.
The driver's window switch has an express
-down
feature that allows the window to be lowered without
holding the switch. Press and hold the side of the
window switch marked AUTO 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.
The power window switch has a lockout feature. This
feature prevents the passenger's windows from
operating except from the driver's position, when the
front driver's side switch is in LOCK. When the switch
is moved to NORM, the rear power windows will
operate again.

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Reducing Speed While Using Cruise Control
There are two ways to reduce your speed while using
cruise control:

Push in the SET button at the end of the lever until
you reach the lower speed you want, then release it.

To slow down in very small amounts, push the
button for less than half a second. Each time you do
this, you'll go 1 mph (1.6 km/h) slower.
Passing Another Vehicle While Using Cruise Control
Use the accelerator pedal to increase your speed. When
you take your foot off the pedal, your vehicle will slow
down to the cruise control speed you set earlier.
Using Cruise Control on Hills
How well your cruise control will work on hills depends
upon your speed, load and the steepness of the hills.
When going up steep hills, you may have to step on theaccelerator pedal to maintain your speed. If the
steepness of the hill causes the vehicle speed to drop
more than 15 mph (24 km/h) below the set speed, your
cruise control will automatically disengage. When going
downhill, you may have to brake or shift to a lower gear
to keep your speed down. Of course, applying the brake
takes you out of cruise control. Many drivers find this to
be too much trouble and don't use cruise control on
steep hills.
Ending Cruise Control
There are two ways to turn off the cruise control:

Step lightly on the brake pedal or

Move the cruise control switch to OFF.
Erasing Speed Memory
When you turn off the cruise control or the ignition,
your cruise control set speed memory is erased.

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2-47 Automatic Headlamp System
When it is dark enough outside, your automatic
headlamp system will turn on your headlamps at the
normal brightness along with other lamps such as the
taillamps, sidemarker, parking lamps and the instrument
panel lights.
To idle your vehicle with the automatic headlamp
system off, set the parking brake while the ignition is
off. Then start the vehicle. The automatic headlamp
system will stay off until you release the parking brake.
The headlamp switch can always be used to turn on the
regular lamps. As with any vehicle, you should turn on
the regular headlamp system when you need it.
Headlamps-On Reminder
A chime will sound when your headlamps are turned on
and your ignition is in OFF, LOCK or ACCESSORY.
Daytime Running Lamps
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the day.
DRL can be helpful in many different driving
conditions, but they can be especially helpful in the
short periods after dawn and before sunset.The DRL system will make your headlamps come on at
a reduced brightness when:

the ignition is on,

the headlamp switch is off,

the parking brake is released and

it is bright enough outside and the automatic
headlamps are off.
When the DRL are on, only your headlamps will be on.
The taillamps, sidemarker and other lamps won't be on.
Your instrument panel won't be lit up either.
When it begins to get dark, your DRL will turn off. Your
headlamps will come on automatically.
When it begins to get bright, the regular lamps will go
off, and your headlamps will change to the reduced
brightness of DRL.
To idle your vehicle with the DRL off, set the parking
brake. The DRL will stay off until you release the
parking brake.
As with any vehicle, you should turn on the regular
headlamp system when you need it.

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2-48 Fog Lamps
Your vehicle has fog lamps. Use them for better vision
in foggy or misty conditions. Your parking lamps and/or
low
-beam headlamps must be on for your fog lamps
to work.
The fog lamp switch is
located to the right of the
instrument panel cluster.
Press the ribbed top part of the switch to turn the fog
lamps on. Press the bottom of the switch to turn them
off. An indicator light will illuminate in the switch when
the fog lamps are on.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps in
the dark without turning on your headlamps.Fog lamps will go off whenever your high
-beam
headlamps come on. When the high
-beams are off, the
fog lamps will come on again.
Headlamp Delay
Your vehicle is equipped with a headlamp delay feature
that holds the headlamps on for a short period of time
after the ignition is turned off.
The HEADLAMP DELAY button is located on the
lower left side of the inside rearview mirror.

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The length of time that the headlamps stay on after the
ignition is turned off can be adjusted by pressing and
holding the HEADLAMP DELAY button. The
delay can be varied in five steps (0, 15, 30, 60 and
90 seconds). When the HEADLAMP DELAY button is
held in, the Light Emitting Diode (LED) on the mirror
will show five step changes in brightness. When the
LED is at its brightest the headlamp delay will be
90 seconds, and when it is most dim the delay will be
zero seconds.
Interior Lamps
Instrument Panel Intensity Control
The instrument panel intensity control is located next to
the parking/headlamp switch. Turn the thumbwheel up
to adjust the instrument panel lights. Turn the
thumbwheel up to the first notch to return the radio
display and gear shift indicator LED display to full
intensity when the headlamps or parking lamps are on.
To turn on the dome lamps (with the vehicle doors
closed) turn the thumbwheel up to the second
notch position.
Exit Lighting and Delayed Illumination
With this feature, your interior lamps will come on and
stay on for up to 25 seconds when entering the vehicle
and up to 5 seconds when leaving your vehicle.
When the doors are opened, the dome lamps will only
come on if the dome lamp button is in the out position.
When all doors are closed or the dome lamp button is
pressed in, the lamps will stay on for a short period of
time and will then fade out.
Dome Lamps
The dome lamps will come on when you open the doors.
You can also turn the dome lamps on by turning the
thumbwheel, located next to the parking/headlamps
switch knob, all the way up to the second notch. In this
position, the dome lamps will remain on whether the
doors are opened or closed.