GM Service Manual Online
For 1990-2009 cars only
Figure 1:

Left Side of the Rear Window Shelf (UE1)


Object Number: 1539154  Size: SF
(1)Vehicle Communication Interface Module (VCIM)
Figure 2:

Inside Rearview Mirror


Object Number: 1539160  Size: MF
(1)Headlight Sensor (DF5)
(2)OnStar® Indicator (UE1)
(3)Emergency Button (UE1)
(4)OnStar® Call Center Button (UE1)
(5)OnStar® Microphone (UE1)
(6)Answer/End Call Button (UE1)
(7)Inside Rearview Mirror (ISRVM) On./Off Button (DF5)
Figure 3:

Roof


Object Number: 1539163  Size: MF
(1)Digital Radio Antenna (U2K)
(2)Cellular/Navigation Antenna (UE1)