The oil pressure sending unit on a Ford 6.0 Power Stroke is located on the driver's side of the engine block, near the front. It's usually a relatively small unit with a single wire connector. However,
the exact location can vary slightly depending on the year and specific modifications to the engine. It's often near the oil filter, but not directly on it.
To be certain, you should consult a repair manual specific to your year and model Ford 6.0 Power Stroke. A visual inspection with the engine bay clean will be the best way to locate it, looking for a sensor near the suggested area. A diagram in a repair manual will be extremely helpful.
