
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Climate Controls 191
Climate Controls
Climate Control Systems
Climate Control Systems . . . . . . . . . . . . . . . 191
Dual Automatic Climate ControlSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
Maintenance
Passenger Compartment Air Filter . . . . . 196
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Climate Control Systems
The heating, cooling, and ventilation in the vehicle can be controlled with this system.
1. Fan Control
2. Air Delivery Mode Controls
3. TEMP (Temperature Control)
4. Recirculation
5. A/C (Air Conditioning)
6. ON/OFF
7. MAX Defrost
8. Rear Window Defogger (If Equipped) or Heated Mirrors (If Equipped)9:Turn clockwise or counterclockwise to
increase or decrease the fan speed.
TEMP : Turn clockwise or counterclockwise
to increase or decrease the temperature
inside the vehicle.
Air Delivery Mode Controls : 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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
192 Climate Controls
To change the current mode, select one or
more of the following. An indicator light will
illuminate:
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.
Avoid using recirculation for long periods of
time in cold or damp conditions. Using
recirculation in cold or damp conditions can
result in window fogging.
A/C : Press to turn the air conditioning on
or off. An indicator light comes on to show
that the air conditioning is enabled. If the
fan is turned off, the air conditioner will not
run. The A/C light will stay on even if the
outside temperatures are below freezing.
Rear Window Defogger
1REAR : If equipped, press to turn the
rear window defogger on or off. An indicator
light on the button comes on to show that
the rear window defogger is on. The rear window defogger only works when
the engine is running. The defogger can be
turned off by turning the vehicle off or to
accessory mode.
If equipped with heated outside mirrors,
press
fto turn them on or off. See
Heated
Mirrors 037.
Caution
Using a razor blade or sharp object to
clear the inside rear window can damage
the rear window defogger. Repairs would
not be covered by the vehicle warranty.
Do not clear the inside rear window with
sharp objects.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
194 Climate Controls
The fan, air delivery mode, air conditioning,
driver and passenger temperatures, and Sync
settings can be controlled by touching
CLIMATE on the infotainment home screen.
A selection can then be made on the front
climate control page displayed.
The fan speed setting appears briefly on the
display screen when the center stack climate
controls are adjusted.
Automatic Operation
The system automatically controls the fan
speed, air delivery, air conditioning, and
recirculation in order to heat or cool the
vehicle to the desired temperature.
When AUTO is lit, all four functions operate
automatically. Each function can also be
manually set and the selected setting is
displayed. Functions not manually set will
continue to be automatically controlled,
even if the AUTO indicator is not lit.
For automatic operation:1. Press AUTO.
2. Set the temperature. Allow the system time to stabilize. Adjust the temperature
as needed for best comfort. To improve fuel efficiency and to cool the
vehicle faster, recirculation may be
automatically selected in warm weather.
The recirculation light will not come on
when automatically controlled. See
@
under
“Manual Operation” for more details.
Manual Operation
9:Press to increase or decrease the fan
speed. The fan speed setting appears on the
main display. Pressing either button cancels
automatic fan control and the fan is
controlled manually.
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.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Climate Controls 195
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.
Avoid using recirculation for long periods of
time in cold or damp conditions. Using
recirculation in cold or damp conditions can
result in window fogging.
A/C : Press to turn the air conditioning on
or off. An indicator light comes on to show
that the air conditioning is enabled. If the
fan is turned off, the air conditioner will not
run. The A/C light will stay on even if the
outside temperatures are below freezing.
Rear Window Defogger
1REAR : If equipped, press to turn the
rear window defogger on or off. An indicator
light on the button comes on to show that
the rear window defogger is on.
The rear window defogger only works when
the engine is running. The defogger can be
turned off by turning the vehicle off or to
accessory mode.
If equipped with heated outside mirrors,
press
fto turn them on or off. See Heated
Mirrors 037.
Caution
Using a razor blade or sharp object to
clear the inside rear window can damage
the rear window defogger. Repairs would
not be covered by the vehicle warranty.
Do not clear the inside rear window with
sharp objects.
Remote Start Climate Control Operation :
If equipped with remote start, the climate
control system may run when the vehicle is
started remotely. If equipped with heated or
ventilated seats or a heated steering wheel,
these features may come on during a remote start. See
Remote Vehicle Start 021,
Heated and Ventilated Front Seats 054, and
Heated Steering Wheel 0105.
Sensors
The solar sensor, on top of the instrument
panel near the windshield, monitors the
solar heat.
The climate control system uses the sensor
information to adjust the temperature, fan
speed, recirculation, and air delivery mode
for best comfort.
Do not cover the sensor; otherwise the
automatic climate control system may not
work properly.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/7/22
Climate Controls 197
3. Press the sides of the glove box doorinward and rotate the door downward to
remove.
4. Pull lever on left side of the filter doorand slide left, then remove the door.
Remove the old filter.
5. Install the new air filter.
6. Reinstall the filter door.
7. Reverse the steps to reinstall the glove box.
See your dealer if additional assistance is
needed.
Service
All vehicles have a label underhood that
identifies the refrigerant used in the vehicle.
The refrigerant system should only be
serviced by trained and certified technicians.
The air conditioning evaporator should never
be repaired or replaced by one from a
salvage vehicle. It should only be replaced
by a new evaporator to ensure proper and
safe operation.
During service, all refrigerants should be
reclaimed with proper equipment. Venting
refrigerants directly to the atmosphere is
harmful to the environment and may also
create unsafe conditions based on
inhalation, combustion, frostbite, or other
health-based concerns. The air conditioning system requires periodic
maintenance. See
Maintenance Schedule
0 394.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 205
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If a brake fade condition is detected, a DIC
warning message is displayed. Adjust brake
pedal use and shift to a lower transmission
gear to reduce braking.
If the brakes continue to fade to a severe
condition, additional DIC messages are
displayed. The brake system warning light
will illuminate, and the vehicle speed may
be limited. See Brake System Warning Light
0 124.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake. 2. Shift into P (Park) and then restart the
engine..If driving uphill when the vehicle
stalls, shift to R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle around.
If the hill is steep enough to stall the
vehicle, it is steep enough to cause it
to roll over.
.If you cannot make it up the hill,
back straight down the hill.
.Never back down a hill in N (Neutral)
using only the brake. The vehicle can
roll backward quickly and you could
lose control.
.If driving downhill when the vehicle
stalls, shift to a lower gear, release
the parking brake, and drive straight
down the hill.
3. If the vehicle cannot be restarted after stalling, set the parking brake, shift into
P (Park), and turn the vehicle off.
3.1. Leave the vehicle and seek help.
3.2. Stay clear of the path the vehicle would take if it rolled downhill.
{Warning
Getting out of the vehicle on the
downhill side when stopped across an
incline is dangerous. If the vehicle rolls
over, you could be crushed or killed.
Always get out on the uphill side of the
vehicle and stay well clear of the
rollover path.
Driving in Mud, Sand, Snow, or Ice
Use a low gear when driving in mud —the
deeper the mud, the lower the gear. Keep
the vehicle moving to avoid getting stuck.
Traction changes when driving on sand. On
loose sand, such as on beaches or sand
dunes, the tires tend to sink into the sand.
This affects steering, accelerating, and
braking. Drive at a reduced speed and avoid
sharp turns or abrupt maneuvers.
Traction is reduced on hard packed snow
and ice and it is easy to lose control. Reduce
vehicle speed when driving on hard packed
snow and ice.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
208 Driving and Operating
For Slippery Road Driving:
.Accelerate gently. Accelerating too quickly
causes the wheels to spin and makes the
surface under the tires slick.
.Turn on Traction Control. SeeTraction
Control/Electronic Stability Control 0236.
.The Antilock Brake System (ABS) improves
vehicle stability during hard stops, but
the brakes should be applied sooner than
when on dry pavement. See Antilock
Brake System (ABS) 0233.
.Allow greater following distance and
watch for slippery spots. Icy patches can
occur on otherwise clear roads in shaded
areas. The surface of a curve or an
overpass can remain icy when the
surrounding roads are clear. Avoid sudden
steering maneuvers and braking while
on ice.
.Turn off cruise control.
Cold Weather Mode
In very low temperatures, a cold weather
message may display on the Driver
Information Center (DIC). The engine speed,
transmission shift patterns, and cabin fan
speed may operate differently to enable the vehicle to warm up quicker. You can
manually override the cabin fan speed in
cold weather mode.
Blizzard Conditions
Stop the vehicle in a safe place and signal
for help. Stay with the vehicle unless there
is help nearby. If possible, use Roadside
Assistance. See
Roadside Assistance Program
0 408. To get help and keep everyone in
the vehicle safe:
.Turn on the hazard warning flashers.
.Tie a red cloth to an outside mirror.
{Warning
Snow can trap engine exhaust under the
vehicle. This may cause exhaust gases to
get inside. Engine exhaust contains
carbon monoxide (CO), which cannot be
seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in snow:
.Clear snow from the base of the
vehicle, especially any blocking the
exhaust pipe.
(Continued)
Warning (Continued)
.Open a window about 5 cm (2 in) on
the vehicle side that is away from the
wind, to bring in fresh air.
.Fully open the air outlets on or under
the instrument panel.
.Adjust the climate control system to
circulate the air inside the vehicle and
set the fan speed to the highest
setting. See“Climate Control Systems.”
For more information about CO, see
Engine Exhaust 0222.
To save fuel, run the engine for short
periods to warm the vehicle and then shut
the engine off and partially close the
window. Moving about to keep warm also
helps.
If it takes time for help to arrive, when
running the engine, push the accelerator
pedal slightly so the engine runs faster than
the idle speed. This keeps the battery
charged to restart the vehicle and to signal
for help with the headlamps. Do this as
little as possible, to save fuel.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
214 Driving and Operating
* Equipment Maximum Weight
Ladder Rack and
Cargo340 kg (750 lb)
Cross Toolbox and
Cargo 181 kg (400 lb)
Side Boxes and
Cargo 113 kg per side
(250 lb per side)
* The combined weight for all
rail-mounted equipment should not
exceed 454 kg (1,000 lb).
Loading Points
1. Primary Load Points 2. Secondary Load Areas
3. GM Approved Accessory Mounting
Points
Structural members (1) and (2) are included
in the pickup box design. Additional
accessories should use these load points.
Depending on the accessory design, use a
spacer under the accessory at the load
points to remove gap. The holes for GM
approved accessories (3) are not intended for
aftermarket equipment. See
www.gmupfitter.com for additional pickup
box load bearing structural information.
Truck-Camper Loading Information
A vehicle-specific Truck-Camper Loading
Information label is attached to the
inside of the vehicle's glove box. This
label indicates if a slide-in camper can
be carried, how much of a load the
vehicle can carry, and how to correctly
spread out the load. It will help to
match the right slide-in camper to the
vehicle.
Your dealer can help make a good
vehicle-camper match and help
determine the Cargo Weight
Rating (CWR). When installing and loading a slide-in
camper, check the manufacturer's
instructions.
When carrying a slide-in camper, the
total cargo load of the vehicle is the
weight of the camper plus:
.Everything added to the camper after
it left the factory.
.Everything in the camper.
.All the people inside.
The CWR is the maximum weight of the
load the vehicle can carry. It does not
include the weight of the people inside.
But, use about 68 kg (150 lb) for
each seat.
The total cargo load must not be more
than the vehicle's CWR.
Refer to the Truck-Camper Loading
Information label in the glove box for
dimensions A and B as shown in the
following illustration.