The oil pressure sending unit on a 1993 Jaguar XJ6 is located on the
engine block, near the oil filter. It's usually a relatively small unit with a single electrical connector. However, the exact position can vary slightly depending on the engine (the AJ6 straight-six is the most likely candidate for a '93 XJ6).
To be certain, you'll need to consult a repair manual specific to your 1993 Jaguar XJ6's engine. A Haynes or a Chilton manual would show a diagram and detailed location. Online resources like the Jaguar forums may also have pictures from other owners who've worked on this area.
