The Engine Control Module (ECM) on a 2001 Chevy Blazer with the 4.3L Vortec engine is typically located
under the hood, on the driver's side fender well. It's often attached to the inner fender apron, sometimes behind a plastic cover or shield. You might need to remove some parts to access it clearly.
It's a good idea to consult a repair manual specific to your year and model Blazer. The manual will have precise diagrams showing the ECM's location and how to access it safely.
