1999 GMC SUBURBAN Owner's Manual

2-84
The following situations can cause the transmission to
operate at higher temperatures:

Towing a trailer

Hot outside air temperatures

Hauling a large or heavy load

Low transmission fluid level

High transmission fluid level

Restricted air flow to the radiator and the auxiliary
transmission oil cooler (if equipped).
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures on
a frequent basis, see ªScheduled Maintenanceº in the
Index for the proper transmission maintenance intervals.TRANS HOT...IDLE ENGINE
Your vehicle has a transmission over-temperature
display contained in the message center.
If this warning message is
displayed, pull the vehicle
off the roadway when it is
safe to do so.
Set the parking brake and place the transmission in
PARK (P). Idle the engine until the message center no
longer displays a message. If idling the engine does not
turn the warning message off after 10 to 15 minutes,
contact your nearest dealer or the GM Roadside Assistance
Center. See ªRoadside Assistanceº in the Index.
NOTICE:
If you keep driving your vehicle with the
transmission TRANS HOT...IDLE ENGINE
message displayed, you can damage the
transmission. This could lead to costly repairs
that may not be covered under your warranty.

2-85
The following situations can cause the transmission to
operate at higher temperatures:

Towing a trailer

Hot outside air temperatures

Hauling a heavy load

Low transmission fluid level

High transmission fluid level

Restricted air flow to the radiator and the auxiliary
transmission oil cooler (if equipped).
A temporary solution to hotter transmission operating
temperatures may be to let the transmission cool down.
If the transmission is operated at higher temperatures on
a frequent basis, see ªScheduled Maintenanceº in the
Index for the proper transmission maintenance intervals.LOW COOLANT
This message is displayed
when the cooling system is
low on coolant.
The engine may overheat. See ªEngine Coolantº in the
Index and have your vehicle serviced as soon as you can.
CHECK COOLANT TEMP
This message is displayed
when the cooling system
temperature gets hot.
Check the coolant temperature gage and the coolant
level. See ªEngine Coolantº and ªEngine Coolant
Temperature Gageº in the Index. See ªEngine
Overheatingº in the Index for further information.

2-86 ENGINE OVERHEATED
This message is displayed
when the cooling system
temperature gets too hot.
This message will be displayed after the air conditioning
system has automatically turned off for the engine
coolant protection mode. See ªEngine Overheatingº
in the Index for further information.
REDUCED ENGINE POWER
This message is displayed
when the cooling system
temperature gets too hot
and the engine further
enters the engine coolant
protection mode.
See ªEngine Overheatingº in the Index for
further information.
CHECK ENG OIL PRESSURE
This message is displayed
when the engine oil pressure
is low.
See ªOil Pressure Gageº in the Index for more information.
CHECK ENG OIL LEVEL
This message is displayed
when the engine oil level
is low.
Once oil is added, it may need time to drain and settle in
the engine before this message will turn off. It is best to
let the engine cool down (if it is hot) or warm up (if it is
cold) and cycle the ignition to be sure this message turns
off. Refer to the dipstick for the correct level.
See ªEngine Oilº in the Index on how to check the oil
level and for what type of oil to add.

2-87 CHANGE ENGINE OIL
This message is displayed
when the engine oil needs
to be changed. The message
is only displayed for
15 seconds at the start of
each ignition cycle.
When you change the engine oil, be sure to reset the
Engine Oil Life System. See ªEngine Oil, When to
Changeº in the Index.
SECURITY
This message is displayed
when the content
theft
-deterrent system
has been activated and
also monitors the
Passlock

System.
If the security message is displayed 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 4WD (If Equipped)
If the SERVICE 4WD
message comes on, there
may be a problem with the
automatic transfer case 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.
LOW WASHER FLUID
This message is displayed
when the vehicle is low on
windshield washer fluid.
The message is only
displayed for 15 seconds
each ignition cycle.
For more information, see ªWindshield Washer Fluidº in
the Index.

2-88 SERVICE RIDE CONTROL
This message is displayed
when a possible problem
exists with the Autoride

system if equipped.
For more information, see ªAutoride
º in the Index.
CARGO DOOR AJAR
This message is displayed
when the rear liftglass,
liftgate or panel doors
are ajar when the ignition
is in RUN.
LOW FUEL
This message is displayed
when your vehicle is low
on fuel.
Refer to the fuel gage for a better indication of the
amount of fuel remaining in the fuel tank.

3-
3-1
Section 3 Comfort Controls and Audio Systems
In this section, you'll find out how to operate the comfort control and audio systems offered with your vehicle.
Be sure to read about the particular systems supplied with your vehicle.
3
-2 Comfort Controls
3
-3 Heater and Air Conditioning Comfort
Controls (If Equipped)
3
-5 Electronic Climate Control System
(If Equipped)
3
-11 Air Conditioning
3
-12 Heating
3
-12 Defogging and Defrosting
3
-12 Rear Window Defogger (If Equipped)
3
-13 Ventilation System
3
-15 Audio Systems
3
-15 Setting the Clock for Systems with
SET Button
3
-15 Setting the Clock for Systems with HR
and MN Buttons
3
-15 AM-FM Stereo3
-17 AM-FM Stereo with Cassette Tape Player
(If Equipped)
3
-19 AM-FM Stereo with Cassette Tape Player
and Automatic Tone Control (If Equipped)
3
-24 AM-FM Stereo with Compact Disc Player
and Automatic Tone Control (If Equipped)
3
-28 Rear Seat Audio (If Equipped)
3
-29 Remote Compact Disc Player (If Equipped)
3
-31 Theft-Deterrent Feature (If Equipped)
3
-34 Understanding Radio Reception
3
-34 Tips About Your Audio System
3
-35 Care of Your Cassette Tape Player
3
-37 Care of Your Compact Discs
3
-37 Care of Your Compact Disc Player
3
-37 Fixed Mast Antenna

3-2
Comfort Controls
Standard Comfort Controls
Fan Knob
The knob on the left side of the control panel adjusts the
fan speed. To increase airflow, turn the knob clockwise.
To decrease airflow, turn it counterclockwise. To turn
the fan off, turn the knob to OFF.
Temperature Knob
The middle knob on the control panel lets you select the
temperature of the air flowing into the passenger area.
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.
VENT: This setting directs the air through the
instrument panel outlets.
BI-LEVEL: Air is delivered through the heater
floor outlets as well as the instrument panel outlets.
The air flow can be divided between VENT and
HEATER depending upon where the knob is placed
between the settings.
HEATER: This setting directs most of the
warmed air through the heater floor outlets, and the rest
of the air is divided between the windshield defroster
outlets and the side window defroster outlets.
BLEND: Airflow is delivered through the heater
floor outlets, the windshield defroster outlets and the
side window defroster outlets. The air flow can be
divided between HEATER and DEFROST depending
upon where the knob is placed between the settings.
DEFROST: This setting directs most air through
the windshield defroster outlets, side window defroster
outlets and some through the heater outlets.

3-3 Heater and Air Conditioning Comfort
Controls (If Equipped)
Fan Knob
The knob on the left side of the control panel adjusts the
fan speed. To increase airflow, turn the knob clockwise.
To decrease airflow, turn it counterclockwise. To turn
the fan off, turn the knob to OFF.
Temperature Knob
The middle knob on the control panel lets you select the
temperature of the air flowing into the passenger area.
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.
PANEL: This setting directs the air through the
instrument panel outlets.
BI-LEVEL: Air is delivered through the
instrument panel outlets and the heater floor outlets.
The air flow can be divided between PANEL and
HEATER depending upon where the knob is placed
between the settings. Pressing the A/C button while
in this mode causes cooler air to come out of the
instrument panel outlets and warmer air to come out
of the heater floor outlets.
HEATER: This setting directs most of the
warmed air through the heater floor outlets as well as
some air through the windshield defroster outlets and
side window defroster outlets.
BLEND: Airflow is delivered through the heater
floor outlets, the windshield defroster outlets and the
side window defroster outlets. The air flow can be
divided between HEATER and DEFROST depending
upon where the knob is placed between the settings.
The air conditioning compressor may run to dehumidify
the air to prevent window fogging.