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 WarningMirrors
Specifications
Inside Rearview Mirror Schematics
Outside Rearview Mirror Schematics
Outside Rearview Mirror Replacement
Preliminary Procedure
Remove the front side door trim. Refer to Front Side
Door Trim Replacement.
Remove the front side door upper trim cove ...
Removal Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface section.
Disable the SIR System. Refer to SIR Disabling
and Enabling.
Disconnect the negative battery cable. Refer to ...
Rear Side Door Adjustment
Rear Side Door
Caution: Refer to Fastener Caution in the Preface section.
Procedure
Loosen the rear door hinge bolt (Qty: 4) to adjust the rear door.
Adjust the rear door in order to obtain an even gap between the rear
door and the roof, the quarter outer panel, the
rocker pan ...