1999 GMC SONOMA climate control

2-31
Engine Exhaust
CAUTION:
Engine exhaust can kill. It contains the gas
carbon monoxide (CO), which you can't see or
smell. It can cause unconsciousness and death.
You might have exhaust coming in if:

Your exhaust system sounds strange
or different.

Your vehicle gets rusty underneath.

Your vehicle was damaged in a collision.

Your vehicle was damaged when driving
over high points on the road or over
road debris.

Repairs weren't done correctly.

Your vehicle or exhaust system had been
modified improperly.
If you ever suspect exhaust is coming into
your vehicle:

Drive it only with all the windows down to
blow out any CO; and

Have your vehicle fixed immediately.
Running Your Engine While You're
Parked (Automatic Transmission)
It's better not to park with the engine running. But if
ever you have to, here are some things to know.
CAUTION:
Idling the engine with the climate control system
off could allow dangerous exhaust into your
vehicle (see the earlier Caution under
ªEngine Exhaustº).
Also, idling in a closed-in place can let deadly
carbon monoxide (CO) into your vehicle even if
the fan switch is at the highest setting. One place
this can happen is a garage. Exhaust
-- with
CO
-- can come in easily. NEVER park in a
garage with the engine running.
Another closed-in place can be a blizzard.
(See ªBlizzardº in the Index.)

2-47 Heated Outside Rearview Mirrors
(If Equipped)
Your vehicle may be
equipped with heated
outside rearview mirrors.
When you operate the
heated mirror button
on your climate control
system, the defogger
will warm the mirrors to
help clear them of ice,
snow or condensation.
Storage Compartments
Glove Box
To open your glove box, lift the lever on the front of the
glove box and lower the door. The glove box should not
be open while driving.
Door Storage
You will find a storage compartment on each door.
Front Storage Area
If your vehicle has this console compartment, squeeze
the front lever while lifting the top to open it. You can
store cassettes and compact discs in the slots in front of
the compartment. There is also a lift
-out storage tray in
the console.

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
-2 Standard Climate Control System
3
-3 Optional Climate Control System
3
-4 Air Conditioning (If Equipped)
3
-4 Heating
3
-5 Defogging and Defrosting
3
-5 Ventilation System
3
-6 Audio Systems
3
-6 Setting the Clock for Systems
with SET Button
3
-6 Setting the Clock for Systems
with HR and MN Buttons
3
-7AM-FM Stereo3
-9AM-FM Stereo with Cassette Tape
Player (If Equipped)
3
-12 AM-FM Stereo with Cassette Tape Player and
Automatic Tone Control (If Equipped)
3
-16 AM-FM Stereo with Compact Disc Player and
Automatic Tone Control (If Equipped)
3
-20 Remote Cassette Tape Player (If Equipped)
3
-22 Theft-Deterrent Feature (If Equipped)
3
-24 Understanding Radio Reception
3
-24 Tips About Your Audio System
3
-25 Care of Your Cassette Tape Player
3
-26 Care of Your Compact Discs
3
-26 Care of Your Compact Disc Player
3
-26 Fixed Mast Antenna

3-2
Comfort Controls
With these systems, you can control the heating, cooling
and ventilation in your vehicle.
Standard Climate Control System
Fan Control
The knob on the left side of the heating system control panel
controls the fan speed. To increase airflow, turn the knob
clockwise. To decrease airflow, turn it counterclockwise.
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. 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.
OFF: This setting turns the system off. Some outside
air will still enter the vehicle whenever the vehicle is
moving forward.
VENT: This setting directs most of the air through
the instrument panel outlets and a small amount through
the floor outlets.
BI-LEVEL: Air is delivered through the heater
floor outlets as well as the instrument panel outlets.
HEATER: This setting directs most of the
warmed air through the heater floor outlets and some
air through the windshield defroster outlets.
BLEND: Airflow is divided equally between the
heater floor outlet and the windshield defroster outlets.
DEFROST: This setting directs most air through
the windshield defroster outlets and some through the
heater outlets.

3-3 Optional Climate Control System
Fan Control
The knob on the left side of the heating system
control panel controls the fan speed. To increase airflow,
turn the knob clockwise. To decrease airflow, turn
it counterclockwise.
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. 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.
OFF: This setting turns the system off. Some outside
air will still enter the vehicle whenever the vehicle is
moving forward.
MAX A/C: This setting provides maximum cooling
with the least amount of work. MAX A/C recirculates
much of the air inside your vehicle so it cools quickly.
This setting directs most of the air through the
instrument panel vents and a small amount through
the floor vents.
A/C: This setting cools the air entering your vehicle and
directs most of the air through the instrument panel
vents and a small amount through the floor vents.
BI-LEVEL A/C: This setting cools the air
entering your vehicle and directs it through the heater
floor outlets as well as the instrument panel outlets.
VENT: This setting directs most of the air through
the instrument panel outlets and a small amount through
the floor outlets. The air conditioning compressor is not
working when VENT is selected.

6-50 Uniform Tire Quality Grading
Quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance.
(This applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter
-type snow
tires, space saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 20 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to Federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course. For
example, a tire graded 150 would wear one and a half
(1 1/2) times as well on the government course as a tire
graded 100. The relative performance of tires depends
upon the actual conditions of their use, however, and
may depart significantly from the norm due to variations
in driving habits, service practices and differences in
road characteristics and climate.
Traction
-- AA, A, B, C
The traction grades, from highest to lowest, are AA,
A, B, and C. Those grades represent the tire's ability to
stop on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight
-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.