To be absolutely sure, you should:
* Consult your owner's manual: This is the best resource for the specific location in your vehicle.
* Look for a wiring harness: The ECM will have several large wiring harnesses connected to it. Follow these harnesses to locate the module.
* Search online for a diagram: Searching "2000 Chevy S10 ECM location diagram" might reveal pictures of its location on similar models.
Be cautious when working near the ECM, as it is a sensitive electronic component.