1999 GMC SIERRA ECO mode

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If the ignition is on but the radio is off, the tape will
begin playing.
Once the tape is playing, use the VOL, AUTO TONE,
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 stopat 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.
REV (4): Press this button to rapidly reverse the tape to
the beginning of the cassette or until you press REV
again. The radio will play the last selected station while
reversing the tape. The tape direction arrow will blink
during the reverse operation.

(5): Press this button to reduce cassette tape noise.
The double
-D symbol will appear on the display while
the player is in this mode.
Dolby Noise Reduction is manufactured under a license
from Dolby Laboratories Licensing Corporation. Dolby
and the double
-D symbol are trademarks of Dolby
Laboratories Licensing Corporation.
FWD (6): Press this button to rapidly forward the tape
to the end of the cassette or until you press FWD again.
The radio will play the last selected station while
forwarding the tape. The tape direction arrow will blink
during the forward operation.
AM
-FM: Press this button to switch from a tape
to the radio.

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TAPE AUX: Press this button to return to the tape
player when playing the radio. The lighted arrow will
appear and show the direction of play when a tape is in
the active mode.
EJECT: Press this button to remove the tape. The
radio will now play. EJECT can be used with either the
ignition or radio off. To load a cassette tape with the
ignition or radio off, press EJECT before loading
the cassette.
CLN: If this message appears on the display, the
cassette tape player needs to be cleaned. It will still play
tapes, but you should clean it as soon as possible to
prevent damage to the tapes and player. See ªCare of
Your Cassette Tape Playerº in the Index. After you clean
the player, press and hold EJECT for five seconds to
reset the CLN indicator. The radio will display
--- to
show the indicator was reset.CD Adapter Kits
It is possible to use a CD adapter kit with your cassette
tape player after activating the bypass feature on your
tape player.
To activate the bypass feature, use the following steps:
1. Turn the ignition to RUN or ACCESSORY.
2. Turn the radio off.
3. Press and hold the TAPE AUX button for five
seconds. The tape symbol on the display will flash
for two seconds, indicating the feature is active.
4. Insert the adapter. It will power up the radio and
begin playing.
This override routine will remain active until EJECT
is pressed.

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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 AUTO TONE to select the setting you prefer.
5. 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 and the tone you selected
will be automatically selected for that button.
6. 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 stored 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. When the
BASS control is rotated, the AUTO TONE display will
go blank.
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. When
the TREB control is rotated, the AUTO TONE display
will go blank. 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.
AUTO TONE: Press this button to select among the
six preset equalization settings and tailor the sound to
the music or voice being heard. Each time you press the
button, the selection will switch to one of the preset
settings of CLASSIC, NEWS, ROCK, POP, C/W
(Country/Western) or JAZZ. To return to the manual
mode, press and release this button until the AUTO
TONE display goes blank. This will return the tone
adjustment to the BASS and TREB controls. If a BASS
or TREB control is rotated, the AUTO TONE display
will go blank. Use PUSHBUTTONS to program
AUTO TONE.

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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 Compact Disc
PWR: Press this knob to turn the system on. (Please note
that you can also turn the system on when you insert a
compact disc into the player with the ignition on.)
Insert a disc partway into the slot, label side up. The
player will pull it in. Wait a few seconds and the disc
should play. CD and a CD symbol will also appear on
the display. Anytime you are playing a CD, the letters
CD will be next to the CD symbol.If the disc comes back out and 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.)

The 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.
Press RECALL to make ERR go off the display.
PREV (1): Press PREV or the SEEK left arrow to
search for the previous selection. If you hold this button
or press it more than once, the disc will advance further.
Sound is muted in this mode.
RDM (2): Press this button to play the tracks on the disc
in random order. While in the RDM mode, RANDOM
appears on the display. Press RDM again to return to
normal play.
NEXT (3): Press NEXT or the SEEK right arrow to
search for the next selection. If you hold this button or
press it more than once, the disc will advance further.
The next track number will appear on the display. Sound
is muted in this mode.

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REV (4): Press and hold REV to return rapidly to a
favorite passage. You will hear the disc selection play at
high speed while you press the REV button. This allows
you to listen and find out when the disc is at the desired
selection. Release REV to resume playing.
FWD (6): Press and hold this button to advance rapidly
within a track. You will hear the disc selection play at
high speed while you press the FWD button. This allows
you to listen and find out when the disc is at the desired
selection. Release FWD to resume playing.
RECALL: Press this button to see what track is playing.
Press it again within five seconds to see how long the
CD has been playing that track. Elapsed time is
displayed in minutes and tenths of a second. The track
number will also appear when a new track begins to
play. Press RECALL again to return to the time display.
AM
-FM: While in the CD mode, press this button to
stop playing the CD and play the radio. The CD symbol
will still display but the word CD will be replaced with
either AM, FM1 or FM2. (If the radio is turned off, the
disc stays in the player and will resume playing at the
point where it stopped.)CD AUX: To switch between the player and the radio
when a disc is playing, press the AM
-FM button. To
return to the player, press CD AUX. When a disc is
playing, the letters CD and the CD symbol will appear
on the display. (If the radio is turned off, the disc stays
in the player and will resume playing at the point where
it stopped.)
EJECT: Press this button to eject the disc from the
player and play the radio. When the same or a new disc
is inserted, the disc will start playing on track one. If a
compact disc is left sitting in the opening for more than
a few seconds, the player will pull the CD back in. The
radio will continue playing. When the ignition is off,
press this button to load a CD.

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NEXT (3): Press this button to advance to the next track
on the disc.
REV (4): Press and hold this button to quickly reverse
within a track. As the CD reverses, elapsed time will be
displayed to help you find the correct passage.
FWD (6): Press and hold this button to quickly advance
within a track. As the CD advances, elapsed time will be
displayed to help you find the correct passage.
SEEK: Press the left arrow while playing a CD to go
back to the start of the current track. It will go back to
the current track if more than eight seconds have played.
Press the left arrow again to go to previous tracks. Press
the right arrow to go to the next higher track on the disc.
RANDOM: Press P.SCAN to enter the random play
mode. RANDOM will appear on the display. While in
this mode, the tracks on the disc will be played in
random order. If you press SEEK, PREV or NEXT
while in the random mode, the previous or next track
will be scanned randomly. Press P.SCAN again to turn
off RANDOM and return to normal operation.
RECALL: Press this button to see what track is
currently playing. Press RECALL again within five
seconds to see how long the track has been playing.When a new track starts to play, the track number will
also appear. Press RECALL a third time and the time of
day will be displayed.
TAPE AUX: With a disc loaded in the player and the
radio playing, press this button once to play the compact
disc. To return to playing the radio, press AM
-FM.
If both a cassette tape and CD are loaded, press TAPE
AUX to switch between the tape and compact disc.
EJECT: Press this button on the remote player to eject
a compact disc.
Theft-Deterrent Feature (If Equipped)
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.

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Use one of the following charts to determine how much
your vehicle can weigh, based upon your vehicle model
and options.
Maximum trailer weight is calculated assuming the
driver and one passenger are in the tow vehicle and it
has all the required trailering equipment. The weight of
additional optional equipment, passengers and cargo in
the tow vehicle must be subtracted from the maximum
trailer weight.
Above the 2,000 lbs. (908 kg) trailer rating, the engine
oil cooler is required on C/K
-2500 models with gas
engines. Refer to the Trailering Guide for oil cooler
recommendations.C
-1500 (2WD)
Engine (Trans.) Axle Ratio Max. Trailer Wt.
5.0L 3.08 4,500 lbs. (2 043 kg)
3.42 5,500 lbs. (2 497 kg)
3.73 6,500 lbs. (2 951 kg)
5.7L 3.08 5,000 lbs. (2 270 kg)
3.42 6,000 lbs. (2 724 kg)
3.73 7,000 lbs. (3 178 kg)
K
-1500 (4WD)
Engine (Trans.) Axle Ratio Max. Trailer Wt.
5.0L 3.42 5,000 lbs. (2 270 kg)
3.73 6,000 lbs. (2 724 kg)
5.7L 3.42 5,500 lbs. (2 497 kg)
3.73 6,500 lbs. (2 951 kg)
6.5L Diesel 3.42 6,000 lbs. (2 724 kg)
3.73 7,000 lbs. (3 178 kg)

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6-26 C3 (3500 HD) Trucks Equipped with Dana
Rear Axle
Additional rear axle scheduled maintenance is required
on 3500 HD models equipped with Dana rear axles
when they are driven under the following conditions:

Extreme loading (at or near GVWR) or trailer
towing, and:

Operation above 45 mph (70 km/h) for extended
periods of time
Vehicles used in any of these conditions require the
rear axle lubricant be changed every 30,000 miles
(50 000 km). Fluid capacity is 4.12 quarts (3.9 L).
Four-Wheel Drive
Most lubricant checks in this section also apply to
four
-wheel-drive vehicles. However, they have two
additional systems that need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine how
often to check the lubricant. See ªPeriodic Maintenance
Inspectionsº in the Index.How to Check Lubricant
If the level is below the bottom of the filler plug hole,
you'll need to add some lubricant. Add enough lubricant
to raise the level to the bottom of the filler plug hole.
Use care not to overtighten the plug.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.