Where is the oil pressure switch of a 1995 Pontiac Transport Do you have to remove timing chain replace it?

The oil pressure switch on a 1995 Pontiac Transport is located on the engine block, near the oil filter. You do not have to remove the timing chain to replace it. Access is typically pretty straightforward; you might need to remove some other components (like the oil filter for better access) depending on the exact engine (2.0L or 3.1L). A shop manual specific to your vehicle's year and engine would give you the precise location and best removal procedure.