2004 GMC YUKON wiring

Lockout Protection
This feature protects you from locking your key in the
vehicle when the key is in the ignition and a door
is open.
If the power lock switch is pressed when a door is open
and the key is in the ignition, all of the doors will lock
and then the driver’s door will unlock.
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 not see or smell CO. It can
cause unconsciousness and even death.
CAUTION: (Continued)
CAUTION: (Continued)
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
Climate Control System on page 3-22.
If you have air outlets on or under the
instrument panel, open them all the way.
SeeEngine Exhaust on page 2-42.
2-13

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 four positions:
9(Off):Turning the control to this position turns off
the Daytime Running Lamps (DRL) and the automatic
headlamps.AUTO (Automatic):Turning the control to this position
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)
5(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 pushing the turn signal/high-beam lever towards
the instrument panel.
A circuit breaker protects your headlamps. If you have
an electrical overload, your headlamps will icker on and
off. Have your headlamp wiring checked right away if
this happens.
3-15

Fog Lamps
If your vehicle has fog lamps, use them for better vision
in foggy or misty conditions.
The fog lamp button is
located on the left side of
the instrument panel.
Your parking lamps and/or low-beam headlamps must
be on for your fog lamps to work.
Press the button to turn the fog lamps on. Press the
button again to turn them off. An indicator light will glow
in the button when the fog lamps are on.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps
in the dark without turning on your headlamps.
The fog lamps will go off whenever your high-beam
headlamps come on. When the high beams go off, the
fog lamps will come on again.The fog lamps will be cancelled after the ignition is
turned off. If you still want to use the fog lamps after you
restart the vehicle, you will need to press the fog
lamp button again.
Auxiliary Roof Mounted Lamp Switch
If your vehicle has this feature, this switch includes
wiring provisions for a dealer or a qualied service
center to install an auxiliary roof lamp.
This switch is located on
the center of the
instrument panel near the
comfort controls.
When the switch wiring is connected to an auxiliary roof
mounted lamp, pressing the switch will activate the lamp
and illuminate an indicator light near the switch. Pressing
the switch again will turn off the roof mounted lamp.
3-18

Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel cluster, 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 passenger sensing
system (if equipped), the wiring and the crash sensing
and diagnostic module. For more information on the
air bag system, seeAir Bag Systems on page 1-72.
This light will come on
when you start your
vehicle, and it will ash 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.
Passenger Air Bag Status Indicator
If your vehicle has the passenger sensing system
your rearview mirror will have a passenger air bag status
indicator.
When the ignition key is turned to RUN or START, the
passenger air bag status indicator will light ON and
OFF, or the symbol for on and off, for several seconds
as a system check. Then, after several more seconds,
the status indicator will light either ON or OFF, or either
the on or off symbol to let you know the status of the
right front passenger’s frontal air bag.
Passenger Air Bag Status Indicator – United States
Passenger Air
Bag Status
Indicator – Canada
3-43

Trailer Wiring Harness
Your vehicle is equipped with the following wiring
harnesses for towing a trailer.
Basic Trailer Wiring
The trailer wiring harness, with a seven-pin connector,
is located at the rear of the vehicle and is tied to
the vehicle’s frame. The harness connector can be
plugged into a seven-pin universal heavy-duty trailer
connector available through your dealer.The seven-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed
Dark Blue: Trailer Brake
4-75

Heavy-Duty Trailer Wiring Harness
Package
Your vehicle is equipped with the seven-wire trailer
towing harness. This harness with a seven-pin universal
trailer connector is attached to a bracket on the hitch
platform.The seven-wire harness contains the following trailer
circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed
Dark Blue: Trailer Brake
If your trailer is equipped with electronic brakes, you
can get a jumper harness (electric trailer brake control)
with a trailer battery feed fuse from your dealer. This
harness and fuse should be installed by your dealer or a
qualied service center.
If you need to tow a light-duty trailer with a standard
four-way round pin connector, you can also get an
adapter.
4-76

Instrument Panel Jumper Wiring Harness
{CAUTION:
Be sure to use only the correct trailer brake
harness, the one intended for use on your
vehicle. If you use some other trailer brake
harness, even if it seems to t, your trailer
brakes may not work at all. You could have a
crash in which you or others could be injured.
Use only the trailer brake harness intended for
your vehicle. If it is no longer available to you,
be sure to get a proper replacement from your
dealer.This harness is included with your vehicle as part of the
heavy-duty trailer wiring package.
This harness is for an electric brake controller and
includes a trailer battery feed fuse. It should be installed
by your dealer or a qualied service center.
This harness is new for your vehicle, and you will not be
able to use a harness from an earlier model year.
4-77

Four-Wire Harness Adapter
This adapter is included
with your vehicle as part of
the heavy-duty trailer
wiring package.
Use this adapter to connect a standard four-way round
pin connector to the seven-wire harness on your vehicle.Connect the adapter with the tab pointing up (see
arrow). The ip cap on the vehicle’s seven-wire harness
will lock onto the tab and help hold the adapter in
place. Plug the four-way round pin connector onto the
adapter.
4-78