comfort GMC YUKON 2001 User Guide

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.

3-4
DEFROST: This setting directs most of the air
through the windshield defroster outlets, side window
defroster outlets and some air through the heater outlets.
When in the DEFROST mode, the air conditioning
compressor may run to dehumidify the air to prevent
window fogging.
OUTSIDE AIR: Press this button to direct
the system to use outside air. This is the setting which
should be used for normal operation.
Pressing the OUTSIDE AIR button will cancel the
RECIRCULATION button.
RECIRCULATION: Press this button to
limit the amount of outside air entering your vehicle.
This is helpful when you are trying to limit odors
entering your vehicle or attempting to quickly cool
down the interior. Pressing RECIRCULATION will
recirculate air continuously.
RECIRCULATION is used when the fan control is OFF
to limit odors, outside air and dust from entering your
vehicle. All button lights will go off. The last setting
selected will activate when the blower is turned back on.
Pressing the RECIRCULATION button will cancel
the OUTSIDE AIR button. To return to normal
operation and to prevent stale air, be sure to return
the OUTSIDE AIR.Between HEATER and BLEND mode, outside air is forced
to reduce window fogging. If the RECIRCULATION
button is pressed, the LED indicator will flash three times
indicating that forced outside air is activated and
RECIRCULATION is not available.
The auto recirculation feature will activate when the
following are true:

the air conditioning system is activated,

the OUTSIDE AIR button is on, and

the vehicle load is high due to city traffic, extended
idling or hot weather.
The system will automatically switch to the recirculation
mode to lower the system load and improve interior
comfort. The OUTSIDE AIR and RECIRCULATION
button LEDs will not change. The system will return
to the OUTSIDE AIR function when the system load
is reduced.
A/C: Press this button to turn the air conditioning
on and off. The system will cool and dehumidify the air
inside the vehicle when the A/C light is on.
Air conditioning will be automatically disabled when
the outside temperature drops below a level at which
air conditioning is effective.

3-6
Mode Knob - Automatic Operation
The right knob on the control panel allows you to
choose the direction of air delivery. When the system is
set for automatic operation, sensors will control the air
delivery mode. Air will come primarily from the floor or
instrument panel outlets, with some air directed to the
windshield to prevent fogging.
When the system is in AUTO mode, the air conditioning
light will turn on, and the recirculation and outside air
lights turn off. With the system in full auto control
(both the fan and mode knobs in AUTO), you still
have the ability to override any function. However,
continually overriding the outside air or the A/C
compressor will limit the ability of the system to
cool the vehicle quickly.
If you push a button for a function which is not
available, the light next to that button will flash
three times to alert you that it's not available.
To find your comfort zone, start with the 74
F (23
C)
setting and allow about 20 minutes for the system to
adjust the temperature if necessary.With the automatic setting, the air conditioning
compressor automatically cycles when needed to cool
the air. In cold weather, when the system senses the
need for heat, the airflow will be directed out of the
floor outlets. As the interior temperature approaches a
desired setting, the fan speed will decrease. To maintain
interior comfort, the airflow will adjust between the
instrument panel air outlets and floor outlets. On bright
sunny days in cool weather, the airflow may come out
of the air conditioning and floor outlets (bi
-level mode)
to maintain comfort and prevent stuffiness.
To avoid blowing cold air in cold weather, the system will
delay turning on the fan until warm air is available. The
length of delay depends on the outside air temperature,
engine coolant temperature or the time since the engine
was last started. As the coolant warms up, the blower
fan speed will gradually increase and air will flow from
the heater outlets, with some airflow to the windshield
to prevent fogging under most normal conditions.
Be careful not to put anything over the solar sensor
located around the center of the instrument panel.
This sensor is used by the automatic system to
regulate temperature.

3-11 Air Conditioning
On hot days, open the windows long enough to let hot
air inside escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work its best.
The RECIRCULATION button allows the air inside
your vehicle to be recirculated. This setting helps to
maximize your air conditioner's performance and your
vehicle's fuel economy. This setting also cools air the
fastest and can be used to keep unwanted odors and/or
dust from entering the vehicle. When using the air
conditioner, turn off the RECIRCULATION button after
the vehicle reaches a comfortable interior temperature.
When the right knob on the control panel is between
HEATER and DEFROST, the recirculation feature will
not function to reduce window fogging.The A/C button, below the mode knob, allows the air
coming into your vehicle to be cooled. This setting is
useful for normal cooling on hot days. When you use
A/C with the RECIRCULATION button pushed in,
turn off recirculation as soon as the vehicle reaches a
comfortable interior temperature.
Maximum air conditioning performance is obtained by
pressing the A/C button, the RECIRCULATION button
and turning the temperature knob fully counterclockwise
to the blue area. This setting also cools air the fastest.
After the vehicle's interior reaches a comfortable
temperature, press the OUTSIDE AIR button to
place the air conditioning system in the normal mode.
Passenger Compartment Air Filter (If Equipped)
If your vehicle has air conditioning, it is equipped with
a passenger compartment air filter, which filters outside
air entering the vehicle. For information on replacing
the filter see ªPassenger Compartment Air Filterº in
the Index.

3-33 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.To help avoid hearing loss or damage:

Adjust the volume control to the lowest setting.

Increase volume slowly until you hear comfortably
and clearly.
NOTICE:
Before you add any sound equipment to your
vehicle
-- like a tape player, CB radio, mobile
telephone or two
-way radio -- be sure you
can add what you want. If you can, it's very
important to do it properly. Added sound
equipment may interfere with the operation of
your vehicle's engine, Delphi Delco Electronics
radio or other systems, and even damage them.
Your vehicle's systems may interfere with the
operation of sound equipment that has been
added improperly.
So, before adding sound equipment, check with
your dealer and be sure to check Federal rules
covering mobile radio and telephone units.

4-37
Once you are moving on the freeway, make certain you
allow a reasonable following distance. Expect to move
slightly slower at night.
When you want to leave the freeway, move to the proper
lane well in advance. If you miss your exit, do not,
under any circumstances, stop and back up. Drive on
to the next exit.
The exit ramp can be curved, sometimes quite sharply.
The exit speed is usually posted.
Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are going
slower than you actually are.
Before Leaving on a Long Trip
Make sure you're ready. Try to be well rested. If you
must start when you're not fresh
-- such as after a day's
work
-- don't plan to make too many miles that first part
of the journey. Wear comfortable clothing and shoes you
can easily drive in.Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it's ready to go. If it needs
service, have it done before starting out. Of course,
you'll find experienced and able service experts in
GM dealerships all across North America. They'll be
ready and willing to help if you need it.
Here are some things you can check before a trip:

Windshield Washer Fluid: Is the reservoir full?
Are all windows clean inside and outside?

Wiper Blades: Are they in good shape?

Fuel, Engine Oil, Other Fluids: Have you checked
all levels?

Lamps: Are they all working? Are the lenses clean?

Tires: They are vitally important to a safe,
trouble
-free trip. Is the tread good enough for
long
-distance driving? Are the tires all inflated
to the recommended pressure?

Weather Forecasts: What's the weather outlook
along your route? Should you delay your trip a
short time to avoid a major storm system?

Maps: Do you have up
-to-date maps?

4-38
Highway Hypnosis
Is there actually such a condition as ªhighway hypnosisº?
Or is it just plain falling asleep at the wheel? Call it
highway hypnosis, lack of awareness, or whatever.
There is something about an easy stretch of road with
the same scenery, along with the hum of the tires on the
road, the drone of the engine, and the rush of the wind
against the vehicle that can make you sleepy. Don't let
it happen to you! If it does, your vehicle can leave the
road in less than a second, and you could crash and
be injured.
What can you do about highway hypnosis? First, be
aware that it can happen.
Then here are some tips:

Make sure your vehicle is well ventilated, with a
comfortably cool interior.

Keep your eyes moving. Scan the road ahead
and to the sides. Check your mirrors and your
instruments frequently.

If you get sleepy, pull off the road into a rest, service
or parking area and take a nap, get some exercise,
or both. For safety, treat drowsiness on the highway
as an emergency.
Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in flat or rolling terrain.

4-43
CAUTION:
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill
you. You can't see it or smell it, so you might not
know it is in your vehicle. Clear away snow from
around the base of your vehicle, especially any
that is blocking your exhaust pipe. And check
around again from time to time to be sure snow
doesn't collect there.
Open a window just a little on the side of the
vehicle that's away from the wind. This will help
keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little faster
than just idle. That is, push the accelerator slightly.
This uses less fuel for the heat that you get and it
keeps the battery (or batteries) charged. You will need a
well
-charged battery (or batteries) to restart the vehicle,
and possibly for signaling later on with your headlamps.
Let the heater run for a while.
Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.

4-57 Trailer Brakes
If your trailer weighs more than 2,000 lbs. (900 kg)
loaded, then it needs its own brakes
-- and they must
be adequate. Be sure to read and follow the instructions
for the trailer brakes so you'll be able to install, adjust
and maintain them properly.
Your trailer brake system can tap into the vehicle's
hydraulic brake system only if:

The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.

The trailer's brake system will use less than
0.02 cubic inches (0.3 cc) of fluid from your
vehicle's master cylinder. Otherwise, both braking
systems won't work well. You could even lose
your brakes.
If everything checks out this far, make the brake tap
at the port on the master cylinder that sends the fluid
to the rear brakes. But don't use copper tubing for this.
If you do, it will bend and finally break off. Use steel
brake tubing.
Driving with a Trailer
CAUTION:
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon monoxide
(CO) could come into your vehicle. You can't see
or smell CO. It can cause unconsciousness or
death. See ªEngine Exhaustº in the Index. To
maximize your safety when towing a trailer:

Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.

Keep the rear
-most windows closed.

If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle. Do not use
MAX A/C because it only recirculates the
air inside your vehicle. See ªComfort
Controlsº in the Index.