No low oil pressure light

[N41EF]

2000 C230, when you turn the key to on, prior to starting engine, the low oil pressure light doesn't light. Car has no oil pressure gage, so other than car running quiet and at normal temp, I assume oil pressure is ok. Has been this way since I bought it, and only noticed it because I changed the oil today and actually looked for the light to go out. Another item, the cluster low oil level lights just after starting car, showing -2.0 but the oil is perfect on the dipstick. Is the level sender wired to the pressure too? A bad pressure sender? It's the 4 cylinder engine, anyone know where the oil pressure sender scres in to the engine? Thanks folks, Chuck