This oil pressure switch, as designed, will alternate between an opened or closed ground path circuit.
Its only purpose is completing a ground connection, when there is inadequate oil pressure, to illuminate the oil pressure warning light.
Anyways, ForWhatItsWorth, unknowingly sealing the oil pressure switch pipe threads with Too Much Tape
could possibly effectively insulate their pipe threads' ground path connection from each other between the pressure switch and the engine. That's an application where utilizing the appropriate pipe thread sealing compound (generally called pipe dope) is typically a best practice.