GMC Sierra 2015 Owner's Manual page 267

8-10 Climate Controls
3. Close the lower glove box door
and pull it from its frame to
remove the entire unit.
4. Release the two tabs holding the
service door. Open the service
door and remove the old filter.
5. Install the new air filter.
6. Close the service door and
secure the tabs.
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.