Where is the computer located on a 2003 Chevy Trailblazer?

The main computer on a 2003 Chevy Trailblazer, known as the Body Control Module (BCM), is located underneath the dashboard, on the driver's side. It's usually tucked away and may require some disassembly to access. There are also other control modules scattered throughout the vehicle, such as the Transmission Control Module (TCM) and Engine Control Module (ECM), but the BCM is the central computer controlling many of the vehicle's functions.