Page 332 of 518

Black plate (66,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-66 Driving and Operating
While refueling, hang the tethered
fuel cap from the hook on the
fuel door.
{WARNING
Fuel can spray out on you if you
open the fuel cap too quickly.
If you spill fuel and then
something ignites it, you could be
badly burned. This spray can
happen if the tank is nearly full,
and is more likely in hot weather.
Open the fuel cap slowly and wait
for any hiss noise to stop. Then
unscrew the cap all the way.
Be careful not to spill fuel. Do not
top off or overfill the tank and wait a
few seconds after you have finished
pumping before removing the
nozzle. Clean fuel from painted
surfaces as soon as possible. See
Exterior Care on page 10‑98. When replacing the fuel cap, insert
the tether in its hole before
tightening the cap. Turn the fuel cap
clockwise until it clicks. It will require
more effort to turn the fuel cap on
the last turn as you tighten it. Make
sure the cap is fully installed. The
diagnostic system can determine if
the fuel cap has been left off or
improperly installed. This would
allow fuel to evaporate into the
atmosphere. See
Malfunction
Indicator Lamp on page 5‑21.
If the vehicle has a Driver
Information Center (DIC), the
TIGHTEN GAS CAP message
displays if the fuel cap is not
properly installed.
{WARNING
If a fire starts while you are
refueling, do not remove the
nozzle. Shut off the flow of fuel by
shutting off the pump or by
notifying the station attendant.
Leave the area immediately.
Notice: If a new fuel cap is
needed, be sure to get the right
type of cap from your dealer. The
wrong type of fuel cap might not
fit properly, might cause the
malfunction indicator lamp to
light, and could damage the fuel
tank and emissions system. See
Malfunction Indicator Lamp on
page 5‑21.
Page 376 of 518

Black plate (20,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-20 Vehicle Care
{WARNING
Steam and scalding liquids from a
hot cooling system can blow out
and burn you badly. They are
under pressure, and if you turn
the surge tank pressure
cap—even a little —they can
come out at high speed. Never
turn the cap when the cooling
system, including the surge tank
pressure cap, is hot. Wait for the
cooling system and surge tank
pressure cap to cool if you ever
have to turn the pressure cap. If no coolant is visible in the surge
tank, add coolant as follows:
1. Remove the coolant surge tank
pressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about one full
turn. If a hiss is heard, wait for
that to stop. A hiss means there
is still some pressure left.
2. Keep turning the pressure cap slowly and remove it.
3. Fill the coolant surge tank with
the proper mixture to the FULL
COLD mark.
Page 392 of 518

Black plate (36,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-36 Vehicle Care
4. At a wall, measure from theground upward (A) to the
recorded distance from
Step 3 and mark it.
5. Draw or tape a horizontal line (B) on the wall the width of the
vehicle at the height of the mark
in Step 4.
Notice: Do not cover a headlamp
to improve beam cut-off when
aiming. Covering a headlamp may
cause excessive heat build-up
which may cause damage to the
headlamp. 6. Turn on the low-beam
headlamps and place a piece of
cardboard or equivalent in front
of the headlamp not being
adjusted. This allows only the
beam of light from the headlamp
being adjusted to be seen on the
flat surface.
7. Locate the vertical headlamp
aiming screws, which are under
the hood near each headlamp
assembly.
The adjustment screw can be
turned with an E8 Torx
®socket. 8. Turn the vertical aiming screw
until the headlamp beam is
aimed to the horizontal
tape line. Turn it clockwise or
counterclockwise to raise or
lower the angle of the beam.
9. Make sure that the light from theheadlamp is positioned at the
bottom edge of the horizontal
tape line. The lamp on the
left (A) shows the correct
headlamp aim. The lamp on the
right (B) shows the incorrect
headlamp aim.
10. Repeat Steps 7 through 9 for the opposite headlamp.
Page 394 of 518
Black plate (38,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-38 Vehicle Care
4. Press the release tab, if bulbsocket has one, and turn the
bulb socket counterclockwise to
remove it from the taillamp
assembly.
5. Pull the old bulb straight out from the bulb socket.
6. Press a new bulb into the bulb socket.
7. Reinstall the socket into the taillamp assembly by turning the
bulb socket clockwise.
8. Reinstall the taillamp assembly making sure to line up the pins
with the vehicle and tighten the
screws.License Plate Lamp
1. Remove the two screws holdingeach of the license plate lamps
to the molding that is part of the
liftgate. 2. Twist and pull the license plate
lamp assembly forward through
the molding opening.
3. Remove the bulb socket from the lamp assembly by turning it
counterclockwise.
4. Pull the bulb straight out of the socket and install the new bulb.
5. Reverse Steps 1 through 3 to reinstall the license plate lamp.
Page 429 of 518
Black plate (73,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-73
Regular Wheelbase Shown,
Extended Wheelbase Similar
1. Remove the tray to access the tools by pulling up on the finger
depression under the jack
symbol.A. Jack Knob
B. Wing Nut Retaining theTool Bag
C. Wing Nut Retaining the Wheel Blocks
2. Turn the wing nut retaining the tool bag (B) counterclockwise to
remove it.
3. Turn the jack knob (A) counterclockwise to release the
jack and wheel blocks from the
bracket. 4. Turn the wing nut retaining
the wheel blocks (C)
counterclockwise to remove
the wheel blocks and the
wheel block retainer.
Use the following tools:
A. Jack
B. Wheel Blocks
C. Jack Handle
D. Jack Handle Extensions
E. Wheel Wrench
Page 430 of 518
Black plate (74,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-74 Vehicle Care
To access the spare tire, refer to the
following graphics and instructions:
A. Hoist Assembly
B. Hoist Shaft
C. Hoist Shaft Access Cover/Hole
D. Jack Handle Extensions
E. Wheel Wrench
F. Hoist Cable
G. Tire/Wheel Retainer
H. Spare Tire (Valve StemPointed Down)
I. Hoist Shaft Access Hole J. Hoist End of Extension Tool
K. Spare Tire Lock
1. Open the hoist shaft access
door (C) on the bumper to
access the spare tire lock (K).
2. To remove the spare tire lock, insert the ignition key, turn it
clockwise and then pull it
straight out.
3. Assemble the two jack handleextensions (D) and wheel
wrench (E), as shown.
4. Insert the open end of theextension (J) through the hole in
the rear bumper (I) (hoist shaft
access hole).
Be sure the hoist end (J) of the
extension connects to the hoist
shaft. The ribbed square end of
the extension is used to lower
the spare tire.
Page 431 of 518
Black plate (75,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-75
5. Turn the wheel wrenchcounterclockwise to lower the
spare tire to the ground.
Continue to turn the wheel
wrench until the spare tire can
be pulled out from under the
vehicle.
If the spare tire does not lower to
the ground, the secondary latch
is engaged causing the tire not
to lower. See Secondary Latch
System on page 10‑84 for more
information.
6. Use the wheel wrench hook to
pull the hoist cable closer to
assist in reaching the spare tire.
7. Tilt the tire toward the vehiclewith some slack in the cable to
access the tire/wheel retainer.
Separate the retainer from the
guide pin by sliding the retainer
up the pin while pressing down
on the latch.
Page 432 of 518
Black plate (76,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-76 Vehicle Care
Once the retainer is separated
from the guide pin, tilt the
retainer and pull it through the
center of the wheel along with
the cable and latch.
8. Put the spare tire near the flat tire.
Removing the Flat Tire and
Installing the Spare Tire
1. Do a safety check beforeproceeding. See If a Tire Goes
Flat on page 10‑71 for more
information.
2. If the vehicle has a center cap that covers the wheel fasteners,
place the chisel end of the wheel
wrench in the slot on the wheel
and gently pry the cap out. If the wheel has a bolt-on hub
cap, loosen the plastic nut caps
by turning the wheel wrench
counterclockwise. The plastic
nut caps will be retained in the
hub cap after it is removed from
the wheel.3. Use the wheel wrench to loosen
all the wheel nuts. Turn the
wheel wrench counterclockwise
to loosen the wheel nuts. Do not
remove the wheel nuts yet.