Page 196 of 477

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/13/19
Climate Controls 195
The recirculation light will not come
on when automatically controlled.
See
@under“Manual Operation”
for more details.
Manual Operation
9: Turn clockwise or
counterclockwise to increase or
decrease the fan speed. Press the
knob to turn the fan off. When off is
selected, a small amount of air may
still come out of the outlets
depending on vehicle speed. If any
buttons are pressed or knobs are
turned, the climate control system
will turn on and operate at the
current setting.
Press AUTO to return to automatic
operation.
Driver and Passenger
Temperature Control : The
temperature can be adjusted
separately for the driver and
passenger.
Turn the knob clockwise or
counterclockwise to increase or
decrease the driver or passenger
temperature setting. The driver side or passenger side temperature
display shows the temperature
setting increasing or decreasing.
SYNC :
Press to link the passenger
temperature setting to the driver
setting. The SYNC indicator light will
turn on. When the passenger setting
is adjusted, the SYNC indicator light
will turn off.
Air Delivery Mode Control : Press
z,Y, or[to change the
direction of the airflow. Any
combination of the three controls
can be selected. An indicator light
comes on in the selected mode
button.
Changing the mode cancels the
automatic operation and the system
goes into manual mode. Press
AUTO to return to automatic
operation.
To change the current mode, select
one or more of the following:
z: Air is directed to the
windshield, outboard a/c outlets,
and side window outlets.
Y: Air is directed to the a/c outlets.
[:Air is directed to the floor
outlets, with some air directed to the
windshield, outboard a/c outlets,
and side window outlets.
0MAX : Air is directed to the
windshield and the fan runs at a
higher speed if not already above a
medium fan speed. This mode
overrides the previous mode
selected and clears fog or frost from
the windshield more quickly. When
the control is pressed again, the
system returns to the previous mode
setting and fan speed.
For best results, clear all snow and
ice from the windshield before
defrosting.
@: Press to turn on recirculation.
An indicator light comes on. Air is
recirculated to quickly cool the
inside of the vehicle. It can also be
used to help reduce outside air and
odors that enter the vehicle.
Page 337 of 477

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
336 Vehicle Care
Caution
Failure to follow the specific
coolant fill procedure could cause
the engine to overheat and could
cause system damage. If coolant
is not visible in the surge tank,
contact your dealer.
If no coolant is visible in the surge
tank, add coolant.
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.
4. With the coolant surge tank pressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90 °C (195 °F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge
tank until the level reaches the
indicated mark.
5. Replace the pressure cap tightly. 6. Verify coolant level after the
engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1–6.
Caution
If the pressure cap is not tightly
installed, coolant loss and engine
damage may occur. Be sure the
cap is properly and tightly
secured.
Engine Overheating
If the vehicle has the Duramax
diesel engine, see the Duramax
diesel supplement.
Caution
Do not run the engine if there is a
leak in the engine cooling system.
This can cause a loss of all
coolant and can damage the
system and vehicle. Have any
leaks fixed right away.
Page 353 of 477

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
352 Vehicle Care
LED Lighting
This vehicle has several LED lamps.
For replacement of any LED lighting
assembly, contact your dealer.
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps
Base Level Headlamp
Assembly
1. Turn Signal Lamps
Headlamp Replacement
See your dealer for headlamp
replacement.
Turn Signal Lamp
Replacement
Base Level1. Open the hood.
2. Turn the bulb socket counterclockwise to remove it
from the headlamp assembly
and pull it straight out.
3. Remove the bulb by pulling it straight out of the bulb socket.
4. Replace the bulb and reverse Steps 1–3 to reinstall.
Uplevel
See your dealer for headlamp
replacement.
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps
Base Level Taillamp Assembly
1. Stoplamp/Turn Signal Lamp
2. Back-Up Lamp
Uplevel Taillamp Assembly
See your dealer for taillamp
replacement.
It is recommended to replace the
grommets when replacing a bulb.
See your dealer.
Page 354 of 477
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
Vehicle Care 353
To replace one of these bulbs:1. Open the tailgate.
2. Remove the two rear lamp assembly screws.
4. Pull the rear lamp assembly
outward and rearward away
from the box side to remove it
from the vehicle.
5. Turn the bulb socket counterclockwise.
6. Pull the bulb straight out from the socket.
7. Replace the bulb and reverse Steps 1–5 to reinstall.
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp
This procedure is for the regular cab
only. For crew cab and double cab
see your dealer.
1. Cargo Lamp Bulbs
2. Center High-Mounted
Stoplamp (CHMSL) Bulb
Page 355 of 477

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
354 Vehicle Care
To replace one of these bulbs:
1. Remove the two screws and liftoff the lamp assembly.
2. Turn the bulb socket counterclockwise and pull it
straight out.
3. Pull the bulb straight out from the socket.
License Plate Lamp
To replace the bulb:
1. Reach behind the rear bumper and locate the bulb. 2. Turn the bulb socket
counterclockwise and pull the
bulb straight out of the socket.
3. Replace the bulb and reverse
Step 2 to reinstall.
Electrical System
Electrical System
Overload
The vehicle has fuses to protect
against an electrical system
overload. Fuses also protect power
devices in the vehicle.
Replace a bad fuse with a new one
of the identical size and rating.
If there is a problem on the road and
a fuse needs to be replaced, there
are some spare fuses and a fuse
puller in the left instrument panel
fuse block. The same amperage
fuse can also be borrowed. Choose
some feature of the vehicle that is
not needed to use and replace it as
soon as possible.
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have the
headlamp wiring checked right away
if the lamps go on and off or
remain off.
Page 391 of 477
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
390 Vehicle Care
1. Wheel Block (If Equipped)
2. Flat Tire
The following information explains
how to use the jack and change
a tire.
Tire Changing
Removing the Spare Tire and
Tools
1. Jack
2. Jack Knob
3. Tool Kit
4. Wing Nut Retaining Tool Kit
5. Wheel Blocks
6. Wing Nut Retaining WheelBlocks
The equipment is under the second
row seats, if equipped, or behind the
front row seats on regular cab
models. 1. Turn the knob on the jack
counterclockwise to lower the
jack head to release the jack
from its holder.
2. Turn the wing nut counterclockwise to remove the
wheel blocks and the wheel
block retainer.
3. Turn the wing nut used to retain the storage bag and
tools counterclockwise to
remove it.
Use the jack handle extensions and
the wheel wrench to remove the
underbody-mounted spare tire.
Page 392 of 477

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
Vehicle Care 391
1. Spare Tire (Valve StemPointed Down)
2. Tire/Wheel Retainer
3. Hoist Cable
4. Hoist Assembly
5. Hoist Shaft
6. Jack Handle Extensions
7. Wheel Wrench
8. Spare Tire Lock (If Equipped)
9. Hoist Shaft Access Hole
10. Hoist End of Extension Tool
1. Open the spare tire lock cover on the bumper and use the
ignition key to remove the
spare tire lock (8). To remove
the spare tire lock, insert the
ignition key, turn, and pull
straight out.
2. Assemble the wheel wrench (7)and the two jack handle
extensions (6), as shown.
3. Insert the hoist end (open
end) (10) of the extension
through the hole (9) in the rear
bumper.
Do not use the chiseled end of
the wheel wrench.
Be sure the hoist end of the
extension (10) connects to the
hoist shaft. The ribbed square
end of the extension is used to
lower the spare tire.
4. Turn the wheel wrench counterclockwise 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.
5. Pull the spare tire out from under the vehicle.
6. Tilt the tire toward the vehiclewith some slack in the cable to
access the tire/wheel retainer.
Page 393 of 477

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - CRC - 5/14/19
392 Vehicle Care
Tilt the retainer and pull it
through the center of the wheel
along with the cable and
spring.
7. Put the spare tire near the flat tire.
Removing the Flat Tire and
Installing the Spare Tire
Use the following pictures and
instructions to remove the flat tire
and raise the vehicle.
1. Jack
2. Wheel Blocks
3. Jack Handle 4. Jack Handle Extensions
5. Wheel Wrench
The tools you will be using include
the jack (1), the wheel blocks (2),
the jack handle (3), the jack handle
extensions (4), and the wheel
wrench (5).
1. Do a safety check before proceeding. See If a Tire Goes
Flat 0388.
2. If the vehicle has wheel nut
caps, loosen them by turning
the wheel wrench
counterclockwise. If the vehicle has a center cap
with wheel nut caps, the wheel
nut caps are designed to stay
with the center cap after they
are loosened. Remove the
entire center cap.
If the wheel has a smooth
center cap, place the chisel
end of the wheel wrench in the
slot on the wheel, and gently
pry it out.