WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Auxiliary HVAC Control Module
Courtesy of GENERAL MOTORS CORP.
Connect the auxiliary HVAC control module electrical connectors.
Install the auxiliary HVAC control module by pushing the control into the console until the retaining tabs snap into place.