low oil pressure light Cad Northstar engine

I would initially change the oil and filter and sender unit and see if the light goes out if it doesn't I would screw in a mechanical gauge and verify actual pressure. Oil pressure switch is on the engine block near the oil filter I think, has two wires attached to it, tan/black, black/white. Oil pressure should be 5 psi @idle and 35 at 2000 RPM.