For 1990-2009 cars

Control Module | Repair Instruction | Diagnostic System Check | Schematic
--- | --- | --- | ---
Automatic Level Control Module (ALC) | Refer to Automatic Level Control Sensor Replacement in Automatic Level Control | Refer to Diagnostic System Check - Automatic Level Control in Automatic Level Control | Refer to Automatic Level Control Schematics in Automatic Level Control
Body Control Module (BCM) | Refer to Body Control Module Replacement | -- | Refer to Body Control System Schematics
Cellular Communications (OnStar® VIU and Phone) | Refer to OnStar Reconfiguration in Cellular Communication | Refer to Diagnostic System Check - Cellular Communication in Cellular Communication | Refer to one of the following procedures in Cellular Communications:

• | Cellular Telephone Schematics for Cellular Phone

• | OnStar Schematics for OnStar® VIU

Driver Seat Adjuster Memory Module | Refer to Memory Seat Control Module Replacement in Seats | Refer to Diagnostic System Check - Power Seat Systems in Seats | Refer to Memory Seats Schematics in Seats
Electronic Brake Control Module (EBCM) | Refer to Electronic Brake Control Module Replacement in Antilock Brake System | Refer to Diagnostic System Check - ABS in Antilock Brake System | Refer to Antilock Brake System Schematics in Antilock Brake System
Engine Control Module (ECM) | Refer to Engine Control Module Replacement in Engine Controls | Refer to Diagnostic System Check - Engine Controls in Engine Controls | Refer to Engine Controls Schematics in Engine Controls
Entertainment (Radio, IRC and Amplifier) | Refer to one of the following procedures in Entertainment:

• | Radio Speaker Amplifier Replacement for the amplifier

• | Radio Replacement for the base radio

• | Bose Module Replacement for the Bose™ radio

Refer to Diagnostic System Check - Radio/Audio System in Entertainment

Refer to Radio/Audio System Schematics in Entertainment

Heating and A/C Control (HVAC) | Refer to HVAC Control Module Replacement in HVAC - Automatic | Refer to Diagnostic System Check - HVAC Systems - Automatic in HVAC - Automatic | Refer to HVAC Schematics in HVAC - Automatic
Instrument Panel (IPC) | Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console | Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gages, and Console | Refer to Instrument Cluster Schematics in Instrument Panel, Gages, and Console
Power Steering Control Module | Refer to Power Steering Control Module Replacement in Variable Effort Steering | Refer to Diagnostic System Check - Variable Effort Steering in Variable Effort Steering | Refer to Steering Assist Schematics in Variable Effort Steering
Sensing and Diagnostic Module (SDM) | Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement in SIR | Refer to Diagnostic System Check - SIR in SIR | Refer to SIR Schematics in SIR
Sun Roof Actuator Module | Refer to Sunroof Actuator Replacement in Roof | Refer to Diagnostic System Check - Power Sunroof in Roof | Refer to Sunroof Schematics in Roof
Transmission Control Module (TCM) | Refer to Transmission Control Module Replacement in Automatic Transmission - 4L30-E | Refer to Powertrain On Board Diagnostic (OBD) System Check - Automatic Transmission in Automatic Transmission - 4L30-E | Refer to Automatic Transmission Controls Schematics in Automatic Transmission - 4L30-E
Vehicle Theft Deterrent (VTD) | Refer to Theft Deterrent Module Replacement in Theft Deterrent | Refer to Diagnostic System Check - Theft Deterrent in Theft Deterrent | Refer to Theft Deterrent System Schematics in Theft Deterrent