2021 GMC TERRAIN air conditioning

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
2 Introduction
Using this Manual
To quickly locate information about the
vehicle, use the Index in the back of the
manual. It is an alphabetical list of what is
in the manual and the page number where
it can be found.
About Driving the Vehicle
As with other vehicles of this type, failure to
operate this vehicle correctly may result in
loss of control or a crash. Be sure to read
the driving guidelines in this manual in the
section called“Driving and Operating” and
specifically Driver Behavior 0186, Driving
Environment 0186, and Vehicle Design
0 186.
Danger, Warning, and Caution
Warning messages found on vehicle labels
and in this manual describe hazards and
what to do to avoid or reduce them.
{Danger
Danger indicates a hazard with a high
level of risk which will result in serious
injury or death.
{Warning
Warning indicates a hazard that could
result in injury or death.
Caution
Caution indicates a hazard that could
result in property or vehicle damage.
A circle with a slash through it is a safety
symbol which means “Do not,” “Do not do
this,” or“Do not let this happen.”
Symbols
The vehicle has components and labels that
use symbols instead of text. Symbols are
shown along with the text describing the
operation or information relating to a
specific component, control, message, gauge,
or indicator.
M:Shown when the owner’s manual has
additional instructions or information.
*: Shown when the service manual has
additional instructions or information.
0: Shown when there is more information
on another page — “see page.”
Vehicle Symbol Chart
Here are some additional symbols that may
be found on the vehicle and what they
mean. See the features in this manual for
information.
u: Air Conditioning System
G:Air Conditioning Refrigerant Oil
9:Airbag Readiness Light
!:Antilock Brake System (ABS)
$:Brake System Warning Light
9:Dispose of Used Components Properly
P:Do Not Apply High Pressure Water
B:Engine Coolant Temperature
_:Flame/Fire Prohibited
H: Flammable

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
178 Climate Controls
Climate Controls
Climate Control Systems
Climate Control Systems . . . . . . . . . . . . . . . 178
Dual Automatic Climate ControlSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Maintenance
Passenger Compartment Air Filter . . . . . 182
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Climate Control Systems
With this system the heating, cooling, and ventilation in the vehicle can be controlled.
1. Fan Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Defrost
5. TEMP (Temperature Control)
6. Rear Window Defogger
7. Air Recirculation
9:Turn clockwise or counterclockwise to
increase or decrease the fan speed or turn
the fan off. TEMP :
Turn the knob clockwise or
counterclockwise to increase or decrease the
temperature.
Air Delivery Mode Control : Press
Y,\,
[, or-to change the direction of the
airflow. An indicator light comes on in the
selected mode button.
Y: Air is directed to the instrument panel
outlets.
\: Air is divided between the instrument
panel and floor outlets.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Climate Controls 179
[:Air is directed to the floor outlets,
with some to the windshield, side window
outlets, and second row floor outlets.
-: This mode clears the windows of fog or
moisture. Air is directed to the windshield,
floor outlets, and side window vents.
0: Press to clear the windshield of fog or
frost more quickly. Air is directed to the
windshield and the side window vents. The
air conditioning compressor also comes on,
unless the outside temperature is below
freezing.
Do not drive the vehicle until all windows
are clear.
See Air Vents 0182.
A/C : Press to turn the air conditioning
system on or off. An indicator light comes
on to show that the air conditioning is
enabled. The A/C light will stay on even if
the outside temperatures are below freezing
and the compressor does not run. If the fan
is turned off, the air conditioner will
not run.
@: 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.
Rear Window Defogger
The rear window defogger uses a warming
grid to remove fog from the rear window.
K: 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 ignition is on. The defogger turns off if
the ignition is turned to off or to ACC/
ACCESSORY.
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.
Heated Mirror : If equipped with heated
outside mirrors, the mirrors heat to help
clear fog or frost from the surface of the
mirror when the rear window defog button
is pressed. See Heated Mirrors 025.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
180 Climate Controls
Dual Automatic Climate Control System
With this system the heating, cooling, and ventilation in the vehicle can be controlled.
1. Driver Temperature Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger Temperature Control
7. SYNC (Synchronized Temperature)
8. Rear Window Defogger
9. Power Button
10. Air Recirculation
11. AUTO (Automatic Operation) Automatic Operation
The system automatically controls the
following four functions to heat or cool the
vehicle to the desired temperature:
.Fan Speed
.Air Delivery Mode
.Air Conditioning
.Recirculation
When the AUTO indicator light is lit, all four
functions are operating automatically. Each
function can be manually set and the
selected setting will be shown. This cancels full automatic operation and the AUTO
indicator light turns off. Functions that are
not manually set will continue to be
automatically controlled, although the AUTO
indicator light will not be lit.
To place the system in automatic mode:
1. Press AUTO.
2. Set the driver and passenger temperature.
To find your comfort setting, start with
22 °C (72 °F) and allow the system time
to stabilize. Then 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. Press
@to
manually select recirculation; press it again
to select outside air.
Do not cover the solar sensor on the top of
the instrument panel near the windshield.
This sensor regulates air temperature based
on sun load. See “Sensor”later in this
section.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Climate Controls 181
Manual Operation
O:Press to turn the climate control system
on or off. When off, no air will flow into the
vehicle. Turning the fan on, pressing any
other button, or turning a knob will turn the
system back on.
9: Turn clockwise or counterclockwise to
increase or decrease the fan speed. Press the
knob to turn the fan off.
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.
SYNC : Press to link the passenger
temperature settings to the driver setting.
The SYNC indicator light will turn on. When
the passenger temperature settings are
adjusted, the SYNC indicator light is off.
The driver side or passenger side
temperature display shows the temperature
setting increasing or decreasing. Air Delivery Mode Control :
Press
Y,\,
[, or-to change the direction of the
airflow. 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.
Y: Air is directed to the instrument panel
outlets.
\: Air is divided between the instrument
panel and floor outlets.
[: Air is directed to the floor outlets,
with some to the windshield, side window
outlets, and second row floor outlets.
-: This mode clears the windows of fog or
moisture. Air is directed to the windshield,
floor outlets, and side window vents.
0: Press to clear the windshield of fog or
frost more quickly. Air is directed to the
windshield and the side window vents. The
air conditioning compressor also comes on,
unless the outside temperature is below
freezing.
Do not drive the vehicle until all windows
are clear. See
Air Vents 0182.
A/C : Press to turn the air conditioning
system 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 and the A/C compressor may
be off.
@: 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.
Rear Window Defogger
The rear window defogger uses a warming
grid to remove fog from the rear window.
K: 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 ignition is on. The defogger turns off if
the ignition is turned off or to ACC/
ACCESSORY.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Climate Controls 183
2. Disconnect the glove box doordamper (1) from the glove box door
assembly by squeezing the pivot (2) to
release the damper ring.
3. Squeeze both sides of the glove box bininward to lower beyond the stops.
4. Remove the two screws securingthe door. 5. Press the latches on either side of the
service door inward to release. Open the
service door and remove the old filter.
6. Install the new air filter.
7. Close the service door completely.
8. 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.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
184 Climate Controls
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. SeeMaintenance Schedule
0 331.

GMC Terrain/Terrain Denali Owner Manual(GMNA-Localizing-U.S./Canada/
Mexico-14420055) - 2021 - CRC - 11/13/20
Vehicle Care 271
If the engine coolant temperature gauge is
in the overheat zone and an overheat DIC
message is displayed with no sign of steam:1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest fan
speed. Open the windows as necessary.
3. When it is safe to do so, pull off the road, shift to P (Park) or N (Neutral), and
let the engine idle.
If the engine coolant temperature gauge is
no longer in the overheat zone or an
overheat DIC message no longer displays,
the vehicle can be driven. Continue to drive
the vehicle slowly for about 10 minutes.
Keep a safe distance from the vehicle in
front. If the engine coolant temperature
gauge does not go back to the overheat
zone or an overheat DIC message does not
display, continue to drive normally and have
the cooling system checked for proper fill
and function.
If the engine coolant temperature gauge is
still in the overheat zone or an overheat DIC
message still displays, pull over, stop, and
park the vehicle right away. If overheat
messages appear repeatedly, see your
dealer. If there is no sign of steam, idle the engine
for three minutes while parked. If the
engine coolant temperature gauge is still in
the overheat zone or an overheat DIC
message displays, turn off the engine until
it cools down.
Washer Fluid
What to Use
When windshield washer fluid is needed, be
sure to read the manufacturer's instructions
before use. If operating the vehicle in an
area where the temperature may fall below
freezing, use a fluid that has sufficient
protection against freezing.
Adding Washer Fluid
Open the cap with the washer symbol on it.
Add washer fluid until the tank is full. See
Engine Compartment Overview
0261 for
reservoir location.
Caution
.Do not use washer fluid that contains
any type of water repellent coating.
This can cause the wiper blades to
chatter or skip.
.Do not use engine coolant (antifreeze)
in the windshield washer. It can
damage the windshield washer system
and paint.
.Do not mix water with ready-to-use
washer fluid. Water can cause the
solution to freeze and damage the
washer fluid tank and other parts of
the washer system.
.When using concentrated washer fluid,
follow the manufacturer instructions
for adding water.
.Fill the washer fluid tank only
three-quarters full when it is very cold.
This allows for fluid expansion if
freezing occurs, which could damage
the tank if it is completely full.
Brakes
Disc brake pads have built-in wear indicators
that make a high-pitched warning sound
when the brake pads are worn and new