1999 CHEVROLET TAHOE 4WD

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2-22 Automatic Transfer Case (If Equipped)
The transfer case switches are below and to the left of
the climate controls. Use these switches to shift into and
out of four
-wheel drive. You can choose among four
driving settings:
2HI: This setting is used for driving in most situations.
Your front axle is not engaged in two
-wheel drive. This
setting also provides the best fuel economy.
AUTO 4WD: This setting is ideal for use when road
conditions are variable. When driving your vehicle in
AUTO 4WD, the front axle is engaged, but the vehicle's
power is sent only to the rear wheels. When the vehicle
senses a loss of traction, the system will automatically
engage four
-wheel drive. Driving in this mode results in
slightly lower fuel economy than 2HI.
4HI: Use 4HI when you need extra traction, such as
on snowy or icy roads or in most off
-road situations.
This setting also engages your front axle to help drive
your vehicle.
4LO: This setting also engages your front axle and
delivers extra torque. You may never need 4LO. It sends
maximum power to all four wheels. You might choose
4LO if you are driving off
-road in deep sand, deep mud,
deep snow and climbing or descending steep hills.

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2-23
CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the transmission
is in PARK (P). You or someone else could be
seriously injured. Be sure to set the parking
brake before placing the transfer case in
NEUTRAL. See ªParking Brakeº in the Index.
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.

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2-24
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.
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 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 the transmission 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 light will go out.

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2-80 Security Light
This light will come on
briefly when you turn the
key to START.
The light will stay on until the engine starts. If the light
flashes, the Passlock

System has entered a tamper
mode. If the vehicle fails to start, see ªPasslockº in
the Index.
If the light comes on continuously while driving and
stays on, there may be a problem with the Passlock
System. Your vehicle will not be protected by Passlock,
and you should see your GM dealer.
Service Four-Wheel Drive Warning Light
(If Equipped)
If your vehicle is equipped with the automatic
four
-wheel-drive transfer case, it has a computer which
controls the four
-wheel-drive system.
This light should come on
briefly when you turn on the
ignition, as a check to show
you it is working.
The SERVICE 4WD light comes on to indicate that
there may be a problem with the automatic
four
-wheel-drive system and service is required.
Malfunctions can be indicated by the system before
any problem is apparent, which may prevent serious
damage to the vehicle. This system is also designed
to assist your service technician in correctly diagnosing
a malfunction.

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4-48
Vehicle Engine Axle Ratio Max. Trailer Wt.
C
-1500 (2WD) Utility 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) Utility 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)
C
-1500 (2WD) Suburban 5.7L 3.42 5,500 lbs. (2 497 kg)
3.73 6,500 lbs. (2 951 kg)
6.5L Diesel 3.42 5,500 lbs. (2 497 kg)
K
-1500 (4WD) Suburban 5.7L 3.42 5,000 lbs. (2 270 kg)
3.73 6,000 lbs. (2 724 kg)
6.5L Diesel 3.42 5,000 lbs. (2 270 kg)

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4-49
Vehicle Engine Axle Ratio Max. Trailer Wt.
C
-2500 (2WD) Suburban 5.7L 3.73 6,000 lbs. (2 724 kg)
4.10 7,500 lbs. (3 405 kg)
6.5L Diesel 3.73 6,500 lbs. (2 951 kg)
4.10 8,000 lbs. (3 632 kg)
7.4L 3.73 8,500 lbs. (3 859 kg)
4.10 10,000 lbs. (4 540 kg)
K
-2500 (4WD) Suburban 5.7L 4.10 7,000 lbs. (3 178 kg)
6.5L Diesel 3.73 6,000 lbs. (2 724 kg)
4.10 7,500 lbs. (3 405 kg)
7.4L 3.73 8,000 lbs. (3 632 kg)
4.10 10,000 lbs. (4 540 kg)

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6-63
Fuse/Circuit
BreakerUsage
14 4WD Indicator, Cluster, Front and
Rear Comfort Controls (If Equipped),
Instrument Switches, Radio
Illumination, Chime Module
15 DRL Relay, Fog Lamp Relay
16 Front and Rear Turn Signals,
Back
-Up Lamps, BTSI Solenoid
17 Radio (Ignition)
18 4WAL/VCM, ABS, Cruise Control
19 Radio (Battery)
20 PRNDL, Automatic Transmission,
Speedometer, Check Gages,
Warning Lights
21 Security/Steering
22 Not Used
23 Rear Wiper, Rear Washer Pump
24 Front Axle, 4WD Indicator Lamp,
TP2 Relay (Gasoline Engine)
A Power Door Lock, Six
-Way Power
Seat, Keyless Entry Module
B Power WindowsUnderhood Fuse/Relay Center
The underhood fuse/relay center is located in the rear of
the engine compartment near the brake fluid reservoir.
Move the retainer clips for the cover to access the
fuse block.
You can remove fuses with a fuse extractor. The fuse
extractor is mounted to the interior fuse block. To
remove fuses if you don't have a fuse extractor, hold the
end of the fuse between your thumb and index finger
and pull straight out.