WARNING: This page is about a different car, the 2005 Buick LaCrosse and 2005 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Data Link Connector (DLC) Tab
Courtesy of GENERAL MOTORS CORP.
Disengage the data link connector (DLC) tab (1).
Remove the DLC from the instrument panel (I/P) trim pad.