1999 GMC SIERRA ignition

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2-26
Pull the lever, located
just above the parking
brake pedal, marked
BRAKE RELEASE.
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. Always check to be sure
your parking brake is fully released before
you drive.
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.
If you have a 3500 HD model, it is recommended that
the propshaft
-mounted parking brake be burnished as
part of the new vehicle break
-in. The parking brake
will work best after it has been burnished following
these instructions.
Make 10 stops, using the parking brake foot pedal, from
20 mph (32 km/h) about 2 1/2 miles (4 km) apart. In
between stops, drive the vehicle at 20 mph (32 km/h).

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2-28

Move the lever up as far as it will go.
3. If you have four
-wheel drive, 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 (Automatic Transmission Only)
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 with a manual transfer case
shift lever 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.

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2-29
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 (Automatic Transmission)
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)
(Automatic Transmission)
CAUTION:
Before shifting out of PARK (P) you must fully
apply your regular brakes. Your vehicle can roll.
If you have left the engine running, the vehicle
can move suddenly. You or others could be
injured. If you're pulling a trailer, see ªTowing a
Trailerº in the Index.
Your vehicle has a Brake-Transmission Shift Interlock
system (BTSI). 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 to any 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 OFF.

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2-33 Power Windows (If Equipped)
Regular and Extended Cab
Crew Cab
If you have the optional power windows, the controls
are 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.
Press the rear of the switch with the power window
symbol on it to lower the window.
Press the front of the switch with the power window
symbol on it to raise the window.

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2-40
Increasing Speed While Using Cruise Control
There are two ways to go to a higher speed:

Use the accelerator pedal to get to the higher speed.
Press the button at the end of the lever, then release
the button and the accelerator pedal. You'll now
cruise at the higher speed.

Move the cruise switch from ON to R/A. Hold it
there until you get up to the speed you want, and
then release the switch. (To increase your speed in
very small amounts, move the switch to R/A for less
than half a second. Each time you do this, your
vehicle will go about 1 mph (1.6 km/h) faster.)
Reducing Speed While Using Cruise Control
There are two ways to reduce your speed while using
cruise control:

Press in the 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, press 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 the
accelerator 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 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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2-42 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 and

the parking brake is released.
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 indicator light is a
reminder to turn your headlamp switch on. The other
lamps that come on with your headlamps will also
come on.
When you turn off the headlamp switch, 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.
Interior Lamps
Instrument Panel Intensity Control
The instrument panel intensity control is located to the
right of the headlamp switch.
Rotate the thumb wheel up to adjust instrument panel
lights. Rotate the thumb wheel up to the first notch to
return the radio display and gearshift 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) rotate the thumb wheel up to the
second notch position.
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 lamp button is out. When all the 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 go out.

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Compass Operation
Press the COMP switch once briefly to turn the compass
on or off.
When the ignition and the compass feature are on, the
compass will show two character boxes for
approximately two seconds. After two seconds, the
mirror will display the compass heading.
When cleaning the mirror, use a paper towel or similar
material dampened with glass cleaner. Do not spray
glass cleaner directly on the mirror as that may cause the
liquid cleaner to enter the mirror housing.
Compass Calibration
The compass may need calibration if:

After five seconds, the display does not show a
compass heading (ªNº for North, for example), there
may be a strong magnetic field interfering with the
compass. Such interference may be caused by a
magnetic antenna mount, magnetic note pad holder
or a similar magnetic item.

The compass does not display the correct heading
and the compass zone variance is set correctly.
In order to calibrate, the letter ªCº must be displayed in
the mirror compass windows. If ªCº is not displayed,push in the ªCOMPº button for approximately eight
seconds or until the letter ªCº is displayed.
The compass can be calibrated in one of two ways:

Drive the vehicle in circles at 5 mph (8 km/h) or less
until the display reads a direction, or

Drive the vehicle on your everyday routine and after
several turns the compass will become calibrated and
will display a direction.
Compass Variance
The mirror is set in zone eight upon leaving the factory.
It will be necessary to adjust the compass to compensate
for compass variance if you live outside zone eight.
Under certain circumstances, as during a long distance
cross
-country trip, it will be necessary to adjust for
compass variance. Compass variance is the difference
between earth's magnetic north and true geographic
north. If not adjusted to account for compass variance,
your compass could give false readings.
To adjust for compass variance:
1. Press and hold the COMP button (located at the
bottom of the mirror) for three seconds until a zone
number appears in the display.
2. Find your current location and variance zone number
on the following zone map.

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2-65 Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows AIR BAG. The system checks the
air bag's electrical system for malfunctions. The light
tells you if there is an electrical problem. The system
check includes the air bag sensors, the air bag modules,
the wiring and the crash sensing and diagnostic module.
For more information on the air bag system, see
ªAir Bagº in the Index.
This light will come on
when you start your engine,
and it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
engine or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.
The air bag readiness light should flash for a few
seconds when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
AIR BAG OFF Light (Extended Cab Pickup)
When you turn the right front passenger's air bag off, this
light will come on and stay on to remind you that the air
bag has been turned off. This light will go off when you
turn the air bag back on again. See ªAIR BAG OFF
Switchº in the Index for more on this, including
important safety information.