The Black (and silver) Boxes of the 88-89 Reatta
(90-91 has less and diffferent)

From top to bottom, left to right:
First Row: Instrument Panel Cluster (IPC), Cathode Ray Tube (CRT), Body Control Module
Second Row: Central Power Supply, Cassette Player, (upper) Engine Control Module (ECM), (lower) HVAC programmer
Bottom Row: CRT Controller, Radio, TEVES ABS Controller

Top row, from left: Magnavox ignition module, Magnavox Coilpack, Reatta CRT, Riviera CRT
Second Row Center to right: Compass Module, HVAC Blower Module, Headlamp Motor
Bottom Row: Delco Ignition Coil (1 of 3), Delco Ignition Module, Power Antenna

The following four devices are all Engine Control Modules. Note the long slender access cover held in place by two screws. The two on top are service replacement modules. The one on the bottom left with the access cover off is an original unit and has the PROM ID on the upper right corner of the sticker. On the bottom right is a aftermarket replacement that services both modules. I have not found any difference between the 1228253 and the 16198264 other than the part number. It might be a difference in suppliers. Note: as of Dec 2006, GM has superceeded both the -253 and -264 with a p/n 88999198