The location of the main computer module (PCM or Powertrain Control Module) in a 2005 Ford F-250 is
under the hood, typically on the passenger side fender well. However, the exact position can vary slightly depending on the engine and other options. It's usually attached to the inner fender apron, often covered by a plastic shield or shroud.
To be absolutely certain, consult your owner's manual or a repair manual specific to your 2005 Ford F-250. These manuals will have diagrams showing the location of all major modules. You can also search online for images of the engine bay of a 2005 F-250 to get a visual reference.
