tow GMC SIERRA 1999 Owner's Guide

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2-36 Turn Signal and Lane Change Signals
The turn signal has two upward (for right) and two
downward (for left) positions. These positions allow
you to signal a turn or a lane change.
To signal a turn, move the lever all the way up
or down. When the turn is finished, the lever will
return automatically.
An arrow on the instrument
panel will flash in the
direction of the turn or
lane change.
To signal a lane change, just raise or lower the lever
until the arrow starts to flash. Hold it there until you
complete your lane change. The lever will return by
itself when you release it.If you move the lever all the way up or down, and the
arrow flashes at twice the normal rate, a signal bulb
may be burned out and other drivers may not see your
turn signal.
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).
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.

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2-46
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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2-48 Camper-Type Outside Mirrors
(If Equipped)
If your vehicle is equipped with the camper-type
mirrors, they can be adjusted so you can have a clear
view of objects behind you.
1. To adjust the mirrors when hauling a slide-in camper
or towing a trailer, rotate the mirror by pushing the
mirror head toward the front of the vehicle.

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2-50 Electric Outside Rearview Mirrors
(If Equipped)
Select the mirror you want
to move by moving the
center of the switch, located
on the driver's door armrest,
to L (left) or R (right).
Then, adjust the mirror angle by pressing the outer
arrows on the switch until the mirror is adjusted where
you want it.
Convex Outside Mirror
Your passenger's side mirror may be convex. A convex
mirror's surface is curved so you can see more from the
driver's seat.
CAUTION:
A convex mirror can make things (like other
vehicles) look farther away than they really are.
If you cut too sharply into the right lane, you
could hit a vehicle on your right. Check your
inside mirror or glance over your shoulder before
changing lanes.
Storage Compartments
Your vehicle includes a number of storage
compartments for storage of often
-used items.
Some vehicles have storage areas in the instrument
panel. Use these spaces for items such as gloves or
small books.
Some models have a storage pocket on each of the
front doors.
Some vehicles have a storage area behind the seat.
Glove Box
To open your glove box, move the button toward the
passenger's side and pull the door open.

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2-55
There may also be a drawer
that slides out from the
bottom of the console.Your vehicle may have a
removable cupholder at the
front of the console. To
remove the cupholder, pull
the front of the cupholder
toward you and lift up.
To insert the cupholder, place it in the console.
Engage the rear tabs first and then press the front
portion in place.

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2-57
The storage compartment also has a folding writing
table on top of the armrest lid.
To use the writing table, pull the latch at the rear of the
table and swing the writing table forward. Use it to hold
a pad of paper and a pen.
Ashtrays and Cigarette Lighter
Front Ashtray
The front ashtray is located at the bottom of the
instrument panel. Pull on the notch in the ashtray door
to open it.
NOTICE:
If you store paper or other things that burn in
your ashtrays, they could be set on fire by
cigarettes or other smoking materials. That could
cause a fire and possibly damage your vehicle.
Do not store papers and other things that burn in
your ashtrays.
To remove the front ashtray, press the retainer spring
and pivot the ashtray toward you. To replace the ashtray,
place the bottom part of the ashtray on the pivot bar at
the bottom of its mounting on the instrument panel.
Then rotate the ashtray back to its original position.

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You can only drive for a short time with the reading in
either warning zone. If you must drive, turn off all
unnecessary accessories.
Readings in either warning zone indicate a possible
problem in the electrical system. Have the vehicle
serviced as soon as possible.
Brake System Warning Light
When the ignition is on, the brake system warning light
will come on when you set your parking brake. The light
will stay on if your parking brake doesn't release fully.
If it stays on after your parking brake is fully released, it
means you have a brake problem.
Your vehicle's hydraulic brake system is divided into
two parts. If one part isn't working, the other part can
still work and stop you. For good braking, though, you
need both parts working well.
If the warning light comes on, there could be a brake
problem. Have your brake system inspected right away.
This light should come on
briefly when you turn the
ignition key to RUN. If it
doesn't come on then, have
it fixed so it will be ready to
warn you if there's a
problem.
If the light comes on while you are driving, pull off the
road and stop carefully. You may notice that the pedal is
harder to push. Or, the pedal may go closer to the floor.
It may take longer to stop. If the light is still on, have the
vehicle towed for service. (See ªTowing Your Vehicleº
in the Index.)
CAUTION:
Your brake system may not be working properly
if the brake system warning light is on. Driving
with the brake system warning light on can lead
to an accident. If the light is still on after you've
pulled off the road and stopped carefully, have
the vehicle towed for service.

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This light should come on, as a check to show you it is
working, when the ignition is on and the engine is not
running. If the light doesn't come on, have it repaired.
This light will also come on during a malfunction in one
of two ways:

Light Flashing
-- A misfire condition has been
detected. A misfire increases vehicle emissions and
may damage the emission control system on your
vehicle. Dealer or qualified service center diagnosis
and service may be required.

Light On Steady
-- An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis and
service may be required.
If the Light Is Flashing
The following may prevent more serious damage to
your vehicle:

Reducing vehicle speed.

Avoiding hard accelerations.

Avoiding steep uphill grades.

If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.If the light stops flashing and remains on steady, see ªIf
the Light Is On Steadyº following.
If the light continues to flash, when it is safe to do so,
stop the vehicle. Find a safe place to park your vehicle.
Turn the key off, wait at least 10 seconds and restart the
engine. If the light remains on steady, see ªIf the Light
Is On Steadyº following. If the light is still flashing,
follow the previous steps, and drive the vehicle to your
dealer or qualified service center for service.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. See ªFilling Your Tankº in the Index. The
diagnostic system can determine if the fuel cap has been
left off or improperly installed. A loose or missing fuel
cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn the light off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light off.

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3-2
Comfort Controls
Heater Control System
Fan Knob
The knob on the left side of the heating system control
panel controls the fan speed. The knob has four speed
positions. To increase airflow, turn the knob toward HI.
To decrease airflow, turn it toward LO. To turn the fan
off, turn the knob to OFF.Temperature Knob
The middle knob on the control panel lets you select the
relative temperature of the air flowing into the passenger
area of your vehicle. This knob will allow you to adjust
the relative air temperature independently of the function
knob setting. Turn the knob clockwise, toward the red
area, for warmer air. Turn the knob counterclockwise,
toward the blue area, for cooler air.
Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery. The control knob
can be placed in any position between two mode settings
to blend the flow of air.
VENT: This setting directs air through the
instrument panel outlets.
VENT/HEAT: Use this setting to divide airflow
between the floor outlets and instrument panel outlets.
HEATER: This setting directs air through the
floor outlets.
DEFOG: This setting directs air to the heater
outlets and toward the windshield.
DEFROST: This setting directs air toward
the windshield.

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3-3 Heater and Air Conditioning Control
System (If Equipped)
Fan Knob
The knob on the left side of the heating system control
panel controls the fan speed. The knob has four speed
positions. To increase airflow, turn the knob toward HI.
To decrease airflow, turn it toward LO. To turn the fan
off, turn the knob to OFF. If you have the air conditioner
on, turning the fan knob to OFF also turns off the
A/C compressor.
In OFF, while driving, ram airflow will vent to the floor
outlets. The mode knob will not redirect ram airflow to
other selected outlet positions. This is normal operation
for the OFF position.Temperature Knob
The middle knob on the control panel lets you select the
relative temperature of the air flowing into the passenger
area of your vehicle. This knob will allow you to adjust
the relative air temperature independently of the function
knob setting. Turn the knob clockwise, toward the red
area, for warmer air. Turn the knob counterclockwise,
toward the blue area, for cooler air.
Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery. The control knob
can be placed in any position between two mode settings
to blend the flow of air. VENT: This setting directs air through the
instrument panel outlets.
VENT/HEAT: Use this setting to divide airflow
between the floor outlets and instrument panel outlets.
HEATER: This setting directs air through the
heater floor outlets.
DEFOG: This setting directs air to the heater
outlets and toward the windshield.
DEFROST: This setting directs air toward
the windshield.