To be absolutely certain, you should:
* Consult your owner's manual: This is the best resource for the precise location of the ECM in your specific vehicle.
* Check online forums: Search for "1996 Ford F-350 ECM location" on forums dedicated to Ford trucks. You'll likely find photos and descriptions from other owners.
Remember to be careful when working near electrical components in your engine bay. Disconnect the battery's negative terminal before working on any electrical parts.