WARNING: This page is about a different car, the 2002 Cadillac Seville. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Bose Amplifier Scan Tool Output Control
Courtesy of GENERAL MOTORS CORP.
Fig 2: Delco Amplifier Scan Tool Output Control (1 Of 2)
Courtesy of GENERAL MOTORS CORP.
Fig 3: Delco Amplifier Scan Tool Output Control (2 Of 2)