WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Electronic Brake Control Module (EBCM) Connector Terminals And Description (Pin A - D)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Identifying Electronic Brake Control Module (EBCM) Connector Terminals And Description (Pin E - 20)
Courtesy of GENERAL MOTORS CORP.
Fig 3: Identifying Electronic Brake Control Module (EBCM) Connector Terminals And Description (Pin 21 - 29)