To be certain, you should:
* Consult your owner's manual: This is the best resource for the specific location in your vehicle.
* Look for a large black box with numerous connectors: This is the most common visual identifier.
* Check online resources: Websites like Chevrolet forums or repair manuals specific to the 1996 Blazer might have pictures or diagrams showing its location.
Be cautious when inspecting the area around the ECM, as it's an electronic component and should be handled carefully.