lock GMC YUKON 1999 Workshop Manual

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3-5
With the A/C on, turn the temperature knob to MAX for
maximum cooling. This setting also puts the system in
the recirculation mode and helps to maximize your air
conditioner's performance and your vehicle's fuel
economy. This setting also cools the air the fastest. After
the vehicle's interior reaches a comfortable temperature,
turn the temperature knob clockwise to place the air
conditioning system in the normal mode.
Heating
The heater works best if you keep your windows closed
while using it. On cold days, use the HEATER or
VENT/HEAT setting with the temperature knob in
the red area.
If you use the engine coolant heater before starting your
engine in cold weather, 20
F (
-8
C) or lower, your
heating system will produce warmer air faster, to heat
the passenger compartment in cold weather.
The use of an engine coolant heater also reduces the
time it takes for the engine to reach normal operating
temperature, and shortens the time it takes the heater to
reach full output. For more information, see ªEngine
Coolant Heaterº in the Index.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use VENT to direct outside air
through your vehicle. Air will flow through the
instrument panel outlets.
Your vehicle's ventilation system supplies outside air to
the inside of your vehicle when it is moving. With the side
windows closed, air will flow into the front air inlet grilles,
through the vehicle, and out the air exhaust valves.
Outside air will also enter the vehicle when the heater or
the air conditioning fan is running, unless you have the
recirculation button pushed in. For more information on
the recirculation button, see ªAir Conditioningº earlier
in this section.

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3-7 Rear Window Defogger
The lines you see running across the rear window, are
the rear window defogger. The lines warm the glass.
To turn on the rear window
defogger, press this button
next to the fan control knob.
The rear window defogger
will only work if the
ignition switch is turned
to RUN. For best results,
first clear the window
of as much snow or ice
as possible.
The defogger will shut itself off after several minutes. If
you need additional warming time, press the button
again. You can turn the defogger off at any time by
pressing the button.
The rear window defogger button will activate the rear
window defogger and the heated outside rearview mirrors.
Do not attach a temporary vehicle license, tape or decals
across the defogger grid on the rear window.
NOTICE:
Don't use a razor blade or anything else sharp on
the inside of the rear window. If you do, you
could cut or damage the warming grid, and the
repairs wouldn't be covered by your warranty.
Audio Systems
Your Delco Electronics audio system has been designed
to operate easily and give years of listening pleasure.
You will get the most enjoyment out of it if you acquaint
yourself with it first. Find out what your Delco
Electronics system can do and how to operate all its
controls, to be sure you're getting the most out of the
advanced engineering that went into it.
Setting the Clock
Press and hold HR until the correct hour appears on the
display. Press and hold MN until the correct minute
appears on the display. To display the clock with the
ignition off, press RECALL or HR/MN and the time
will be displayed for a few seconds. There is an initial
two
-second delay before the clock goes into the
time
-set mode.

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3-8 AM-FM Stereo with Cassette Tape Player
Included with the AM-FM Stereo with Cassette Tape
Player are six Bose
high performance speakers, an
Acoustimass
bass module and a seven channel Bose
amplifier. Please see your dealer for details.
Playing the Radio
PWR
-VOL: Press this knob to turn the system on and
off. To increase volume, turn the knob clockwise. Turn
it counterclockwise to decrease volume. The knob is
capable of being rotated continuously.
REAR DSPL: When the primary radio is turned on,
press this button to turn the rear seat audio display on
the primary radio on. Press it again to turn the rear seat
audio display off.RECALL: Display the time with the ignition off by
pressing this button. When the radio is playing, press
this button to recall the station frequency.
SCV: Your system has a feature called
Speed
-Compensated Volume (SCV). With SCV, your
audio system adjusts automatically to make up for road
and wind noise as you drive. Set the volume at the
desired level. Turn the control ring behind the upper
knob clockwise to adjust the SCV. Then, as you drive,
SCV automatically increases the volume, as necessary,
to overcome noise at any particular speed. The volume
level should always sound the same to you as you drive.
If you don't want to use SCV, turn the control all the
way down. Each notch on the control ring allows for
more volume compensation at faster vehicle speeds.
Finding a Station
AM
-FM: Press this button to switch between AM, FM1
and FM2. The display will show your selection.
TUNE: Press this knob lightly so it extends. Turn it to
choose radio stations. Push the knob back into its stored
position when you're not using it.
SEEK: Press the right arrow to tune to the next higher
station and the left arrow to tune to the next lower station
and stay there. The sound will mute while seeking.

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SCAN: Press and hold SEEK for two seconds until
SCAN appears on the display. SCAN allows you to
listen to stations for a few seconds. The receiver will
continue to scan and momentarily stop at each station
until you press the button again. The sound will mute
while scanning.
PUSHBUTTONS: The six numbered pushbuttons let
you return to your favorite stations. You can set up to
18 stations (six AM, six FM1 and six FM2). Just:
1. Turn the radio on.
2. Press AM
-FM to select the band.
3. Tune in the desired station.
4. Press and hold one of the six pushbuttons. The sound
will mute. When it returns, release the button.
Whenever you press that numbered button, the
station you set will return.
5. Repeat the steps for each pushbutton.
P. SCAN: The preset scan button lets you scan through
your favorite stations stored on your pushbuttons. Select
either the AM, FM1 or FM2 mode and then press
P. SCAN. It will scan through each station stored on
your pushbuttons and stop for a few seconds before
continuing to scan through all of the pushbuttons. Press P. SCAN again or one of the pushbuttons to stop
scanning to listen to a specific preset station. P. SCAN
will light up on the display while in this mode. If one of
the stations stored on a pushbutton is too weak for the
location you are in, the radio display will show the
channel number (P1
-P6) for several seconds before
advancing to the next preset station.
Setting the Tone
BASS: Press lightly on this knob to release it from its
stored position. Turn the knob clockwise to increase
bass and counterclockwise to decrease bass.
TREB: Press lightly on this knob to release it from its
stored position. Turn the knob clockwise to increase
treble and counterclockwise to decrease treble. If a
station is weak or noisy, you may want to decrease
the treble.
Push these knobs back into their stored positions when
you're not using them.

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Adjusting the Speakers
BAL: Press lightly on this knob to release it from its
stored position. Turn the control clockwise to adjust
sound to the right speakers and counterclockwise to
adjust sound to the left speakers. The middle position
balances the sound between the speakers.
FADE: Press lightly on this knob to release it from its
stored position. Turn the control clockwise to adjust the
sound to the front speakers and counterclockwise for the
rear speakers. The middle position balances the sound
between the speakers.
Push these knobs back into their stored positions when
you're not using them.
Playing a Cassette Tape
Your tape player is built to work best with tapes that are
30 to 45 minutes long on each side. Tapes longer than
that are so thin they may not work well in this player.
To load a cassette tape with the ignition off, press
EJECT or RECALL. Then, insert the cassette tape.
If the ignition is on but the radio is off, the tape will
begin playing.Once the tape is playing, use the VOL, BAL, FADE,
BASS and TREB controls just as you do for the radio.
The tape symbol and a direction arrow will be on the
display whenever a tape is being played. Anytime a tape
is inserted, the top side is selected for play first.
The player automatically senses if the cassette tape is
metal or CrO
2 and adjusts for best playback sound.
For metal tapes, the double
-D symbol will appear on
the display.
PREV (1): Press the PREV button or the SEEK left
arrow to search for the previous selection. A minimum
three
-second blank gap is required for the player to stop
at the beginning of the selection. The tape direction
arrow will blink during the SEEK operation.
PROG (2): Press this button to switch from one side of
the tape to the other.
NEXT (3): Press the NEXT button or the SEEK right
arrow to search for the next selection. A minimum
three
-second blank gap is required for the player to stop
at the beginning of the selection. The tape direction
arrow will blink during the SEEK operation. The sound
will mute while searching for the next selection.

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The rear speakers will be muted when the RSA power is
turned on. You may operate the RSA functions even
when the primary radio is off.
Note that this feature is intended for rear seat passengers.
The following function is controlled by the primary
radio knob:
PWR
-VOL: Push this knob twice to turn RSA off.
The following functions are controlled by the RSA
system buttons:
PWR: Press this button to turn RSA on or off.
VOL: Press this knob lightly so it extends. Turn the
knob clockwise to increase volume and
counterclockwise to decrease volume. Push the knob
back into its stored position when you're not using it.
The upper VOL knob controls the upper headphone and
the lower VOL knob controls the lower headphone.
AM
-FM: Press this button to switch between AM, FM1
and FM2. If the front passengers are already listening to
AM
-FM, the RSA controller will not switch between the
bands and cannot change the frequency.SEEK: While listening to AM
-FM, press the up arrow
to tune to the next higher station and stay there. Press
the down arrow to tune to the next lower station and stay
there. The sound will mute while seeking. The SEEK
button is inactive if the AM
-FM mode on the front radio
is in use.
While listening to a cassette tape, press the up arrow to
hear the next selection on the tape. Press the down arrow
to go back to the previous selection. The SEEK button is
inactive if the tape mode on the front radio is in use.
While listening to a CD, press the up arrow to hear the
next selection on the CD. Press the down arrow to go
back to the start of the current selection (if more than
eight seconds have played). The SEEK button is inactive
in the CD mode if the remote CD player (if equipped) or
the CD changer is in use.
SCAN: Press and hold SEEK until the radio goes into
SCAN mode. SCAN allows you to listen to stations for
a few seconds. The receiver will continue to scan and
momentarily stop at each station until you press SEEK
again. The SCAN function is inactive if the AM
-FM
mode on the front radio is in use.

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Compact Disc Changer Errors
If ERR appears on the display, it could be that:

You are driving on a very rough road. (The disc
should play when the road gets smoother.)

A disc is upside down.

It is dirty, scratched or wet.

It is very humid. (If so, wait about an hour and
try again.)

The disc player is very hot.

The CD changer door is open. Completely close the
changer door to restore normal operation.

An empty magazine is inserted in the CD changer.
Try the magazine again with a disc loaded on one of
the trays.
Press RECALL to make ERR go off the display.
If any error occurs repeatedly or if an error cannot be
corrected, please contact your dealer.Theft-Deterrent Feature
THEFTLOCK is designed to discourage theft of your
radio. It works by using a secret code to disable all radio
functions whenever battery power is removed.
The THEFTLOCK feature for the radio may be used or
ignored. If ignored, the system plays normally and the
radio is not protected by the feature. If THEFTLOCK is
activated, your radio will not operate if stolen.
When THEFTLOCK is activated, the radio will display
LOC to indicate a locked condition anytime battery
power has been interrupted. If your battery loses power
for any reason, you must unlock the radio with the secret
code before it will operate.
Activating the Theft
-Deterrent Feature
The instructions which follow explain how to enter your
secret code to activate the THEFTLOCK system. It is
recommended that you read through all nine steps
before starting the procedure.
NOTE: If you allow more than 15 seconds to elapse
between any steps, the radio automatically reverts to
time and you must start the procedure over at Step 4.

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1. Write down any three or four-digit number from
000 to 1999 and keep it in a safe place separate from
the vehicle.
2. Turn the ignition to ACCESSORY or RUN.
3. Turn the radio off.
4. Press the 1 and 4 buttons together. Hold them down
until
--- shows on the display. Next you will use the
secret code number which you have written down.
5. Press MN and 000 will appear on the display.
6. Press MN again to make the last two digits agree
with your code.
7. Press HR to make the first one or two digits agree
with your code.
8. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show REP to let you know that you
need to repeat Steps 5 through 7 to confirm your
secret code.
9. Press AM
-FM and this time the display will show
SEC to let you know that your radio is secure. The
LED indicator by the volume control will begin
flashing when the ignition is turned off.Unlocking the Theft
-Deterrent Feature After a
Power Loss
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. Turn the ignition on. LOC will appear on the display.
2. Press MN and 000 will appear on the display.
3. Press MN again to make the last two digits agree
with your code.
4. Press HR to make the first one or two digits agree
with your code.
5. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show SEC, indicating the radio is
now operable and secure.
If you enter the wrong code eight times, INOP will
appear on the display. You will have to wait an hour
with the ignition on before you can try again. When you
try again, you will only have three chances to enter the
correct code before INOP appears.
If you lose or forget your code, contact your dealer.

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Disabling the Theft-Deterrent Feature
Enter your secret code as follows; pause no more than
15 seconds between steps:
1. Turn the ignition to ACCESSORY or RUN.
2. Turn the radio off.
3. Press the 1 and 4 buttons together. Hold them down
until SEC shows on the display.
4. Press MN and 000 will appear on the display.
5. Press MN again to make the last two digits agree
with your code.
6. Press HR to make the first one or two digits agree
with your code.
7. Press AM
-FM after you have confirmed that the
code matches the secret code you have written down.
The display will show
---, indicating that the radio is
no longer secured.
If the code entered is incorrect, SEC will appear on the
display. The radio will remain secured until the correct
code is entered.
When battery power is removed and later applied to a
secured radio, the radio won't turn on and LOC will
appear on the display.To unlock a secured radio, see ªUnlocking the
Theft
-Deterrent Feature After a Power Lossº earlier in
this section.
Understanding Radio Reception
AM
The range for most AM stations is greater than for FM,
especially at night. The longer range, however, can
cause stations to interfere with each other. AM can pick
up noise from things like storms and power lines. Try
reducing the treble to reduce this noise if you ever get it.
FM Stereo
FM stereo will give you the best sound, but FM signals
will reach only about 10 to 40 miles (16 to 65 km). Tall
buildings or hills can interfere with FM signals, causing
the sound to come and go.
Tips About Your Audio System
Hearing damage from loud noise is almost undetectable
until it is too late. Your hearing can adapt to higher
volumes of sound. Sound that seems normal can be loud
and harmful to your hearing. Take precautions by
adjusting the volume control on your radio to a safe
sound level before your hearing adapts to it.

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Avoid needless heavy braking. Some people drive in
spurts
-- heavy acceleration followed by heavy
braking
-- rather than keeping pace with traffic. This is a
mistake. Your brakes may not have time to cool between
hard stops. Your brakes will wear out much faster if you
do a lot of heavy braking. If you keep pace with the
traffic and allow realistic following distances, you will
eliminate a lot of unnecessary braking. That means
better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do, the
pedal may get harder to push down. If your engine
stops, you will still have some power brake assist. But
you will use it when you brake. Once the power assist is
used up, it may take longer to stop and the brake pedal
will be harder to push.
Anti-Lock Brakes (ABS)
Your vehicle has anti-lock brakes (ABS). ABS is an
advanced electronic braking system that will help
prevent a braking skid.
When you start your engine and begin to drive away,
your anti
-lock brake system will check itself. You may
hear a momentary motor or clicking noise while this test
is going on. This is normal.
If there's a problem with the
anti
-lock brake system, this
warning light will stay on.
See ªAnti
-Lock Brake
System Warning Lightº in
the Index.