2002 GMC YUKON Electrical

1-38
CAUTION:
Anyone who is up against, or very close to, any
air bag when it inflates can be seriously injured
or killed. Air bags plus lap
-shoulder belts offer
the best protection for adults, but not for young
children and infants. Neither the vehicle's safety
belt system nor its air bag system is designed for
them. Young children and infants need the
protection that a child restraint system can
provide. Always secure children properly in your
vehicle. To read how, see the part of this manual
called ªChildren.º
There is an air bag
readiness light on the
instrument panel,
which shows the air
bag symbol.
The system checks the air bag electrical system for
malfunctions. The light tells you if there is an electrical
problem. See ªAir Bag Readiness Lightº in the Index
for more information.

2-14
Liftgate
CAUTION:
It can be dangerous to drive with the liftgate
glass, liftgate or rear doors open because carbon
monoxide (CO) gas can come into your vehicle.
You can't see or smell CO. It can cause
unconsciousness and even death.
If you must drive with the liftgate glass, liftgate
or rear doors open or if electrical wiring or other
cable connections must pass through the seal
between the body and the liftgate glass, liftgate
or rear doors:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on VENT or OUTSIDE AIR. That will
force outside air into your vehicle. See
ªComfort Controlsº in the Index.

If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.
Liftgate Glass and Liftgate
To open a mechanical lock system from the outside,
insert the key into the lock and turn it counterclockwise
to unlock the glass and liftgate.
The liftgate glass can be opened using the button on the
liftgate after the doors have been unlocked. This can be
done by using either the power door locks or the remote
keyless entry system.
To open the entire liftgate, lift the handle located in the
center of the door.
To lock a power lock system from the outside, insert the
key into the lock button and turn clockwise. All doors
will lock. You may also use the keyless entry system
or the power door locks to lock the liftgate and
liftgate glass.

2-21
When starting your engine in very cold weather (below
0
F or
-18
C), do this:
1. With your foot off the accelerator pedal, turn the
ignition key to START and hold it there up to
15 seconds. When the engine starts, let go of the key.
2. If your engine still won't start (or starts but then
stops), it could be flooded with too much gasoline.
Try pushing your accelerator pedal all the way to
the floor and holding it there as you hold the key in
START for about three seconds. When the engine
starts, let go of the key and accelerator. If the vehicle
starts briefly but then stops again, do the same
thing, but this time keep the pedal down for five or
six seconds. This clears the extra gasoline from
the engine.
NOTICE:
Your engine is designed to work with the
electronics in your vehicle. If you add electrical
parts or accessories, you could change the way
the engine operates. Before adding electrical
equipment, check with your dealer. If you don't,
your engine might not perform properly.
Engine Coolant Heater (If Equipped)
In very cold weather,
0
F (
-18
C) or colder,
the engine coolant
heater can help.
You'll get easier
starting and better
fuel economy during
engine warm
-up.
Usually, the coolant heater should be plugged in a
minimum of four hours prior to starting your vehicle.
At temperatures above 32
F (0
C), use of the coolant
heater is not required.

2-22 To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located on the driver's side of the engine
compartment, near the power steering fluid reservoir.
3. Plug it into a normal, grounded 110
-volt AC outlet.
CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the wrong
kind of extension cord could overheat and cause
a fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't reach, use a
heavy
-duty three-prong extension cord rated for
at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you don't, it could
be damaged.How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead of
trying to list everything here, we ask that you contact
your dealer in the area where you'll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
Automatic Transmission Operation
There are several different positions for your shift lever.

2-45
Exterior Lamps
The control on the driver's side of your instrument panel
operates the exterior lamps.
Turn the control clockwise to operate the lamps.The exterior lamp control has three positions:
(Off): Turning the control to this position turns off all
lamps, except the Daytime Running Lamps (DRL). It
also puts the system into automatic headlamp mode.
(Parking Lamps): Turning the control to this
position turns on the parking lamps, together with
the following:

Sidemarker Lamps

Taillamps

License Plate Lamps

Instrument Panel Lights

Roof Marker Lamps (If Equipped)
(Headlamps): Turning the control to this position
turns on the headlamps, together with the previously
listed lamps and lights.
You can switch your headlamps from high to low
-beam
by pulling on the turn signal/high
-beam lever.
A circuit breaker protects your headlamps. If you have
an electrical overload, your headlamps will flicker on
and off. Have your headlamp wiring checked right away
if this happens.

2-62 Illuminated Visor Vanity Mirror
(If Equipped)
Pull the sun visor down and lift the mirror cover to turn
on the lamps. There is a slide switch to adjust the
brightness of the lamps.
Accessory Power Outlets
With accessory power outlets you can plug in auxiliary
electrical equipment such as a cellular telephone or
CB radio.
Two accessory power outlets are located near the
cigarette lighter. The cigarette lighter is designed to
fit only in the receptacle to the right of the accessory
power outlets.
To use the outlets, lift the cover. When not using them,
always close the cover.
Certain power accessory plugs may not be compatible to
the accessory power outlets and could result in blown
vehicle or adapter fuses. If you experience a problem,
see your dealer for additional information on the
accessory power plugs.
NOTICE:
Adding some electrical equipment to your vehicle
can damage it or keep other things from working
as they should. This wouldn't be covered by your
warranty. Check with your dealer before adding
electrical equipment, and never use anything that
exceeds the fuse rating.
When adding electrical equipment, be sure to follow
the proper installation instructions included with
the equipment.
NOTICE:
Power outlets are designed for accessory plugs
only. Do not hang any type of accessory or
accessory bracket from the plug. Improper use of
the power outlet can cause damage not covered
by your warranty.

2-65

Vehicle Locator Service: To contact the center, call
1
-888-4-ONSTAR. You will be required to provide
your security information. An advisor will send a
command to your vehicle to sound the horn and/or
flash the lamps.

Route Support: An advisor can provide
directions or guidance to most places you want to go.
In addition, they can help you locate gas stations,
rest areas, ATMs, hospitals, hotels, stores, eateries
and more.

Ride Assist: An advisor can locate transportation in
the event that you are unable to drive.

Concierge Services: The concierge advisor can
obtain tickets, reservations or help with vacation/trip
planning and other unique items and services.
OnStar System Limitations
Complete limitations can be found on the Subscriber
Services Agreement. In order to provide you with
excellent service, calls with the OnStar Center may be
monitored or recorded.OnStar Service is:

available in the 48 contiguous United States, Alaska,
Hawaii and Canada;

available when the vehicle is within the operating
range of a cellular provider;

subject to limitations caused by atmospheric
conditions, such as severe weather or topographical
conditions, such as mountainous terrain.

subject to cellular carrier equipment limitations.
Global positioning locating capabilities will not be
available if satellite signals are obstructed.
OnStar will not function if the vehicle's battery is
discharged or disconnected. It may also be inoperative
if the vehicle is in an accident and the OnStar or vehicle
electrical system components are damaged.
OnStar is the communication link between you and
existing governmental emergency and roadside service
providers. OnStar will receive your call and use
reasonable effort to contact an appropriate provider.
OnStar cannot promise that the providers will respond
in a timely manner or at all.

2-74
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual's advice.
Waiting to do repairs can be costly
-- and even
dangerous. So please get to know your warning lights
and gages. They're a big help.
Your vehicle also has a driver information system that
works along with the warning lights and gages. See
ªMessage Centerº in the Index.
Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
come on for about six seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light will
also come on and stay on
for about 20 seconds,
then it will flash for
about 55 seconds.
If the driver's belt is already buckled, neither the chime
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag symbol. The system
checks the air bag's electrical system for malfunctions.
The light tells you if there is an electrical problem.
The system check includes the air bag sensors, the air
bag modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, see ªAir Bagº in the Index.
This light will come on
when you start your vehicle,
and it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.