For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInstallation Procedure
Cut the front compartment front rail in corresponding locations to fit
the remaining original panel. The sectioning joint should be
trimmed to allow a gap of one-and-one-half-times the metal thickness at the
sectioning joint.
Create a 50 mm (2 in) backing plate from the unused porti ...
Rear Side Door Window Replacement
Preliminary Procedures
Position the window approximately half way down in the door.
Remove the water deflector. Refer to Rear Side Door Water Deflector
Replacement.
Remove the outer sealing strip. Refer to Rear Side Door Window Outer
Sealing Strip Replacement.
Rear Side ...
Door Ajar Indicator Description and Operation
Door Ajar Indicator System Components
The door ajar indicator system consists of the following components:
Body control module (BCM)
Instrument cluster
Driver information center
Driver door latch
Passenger door latch
Left rear door latch
Right rear door latch
Liftgate door latch
...