WARNING: This page is about a different car, the 2005 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Seat Track Trim Cover & Lumbar Switch Electrical Connector
Courtesy of GENERAL MOTORS CORP.
Remove the seat track trim cover (1) from the seat.
Disconnect the lumbar switch (2) electrical connector.