Where is the OIL SENDING SWITCH??

I own a 1998 Pontiac Transport which has started to leak oil. It appears to be leaking just in fron of the oil pan (not from the pan itself, from what I could discern). It seems leaking mostly while running (large drops, maybe a couple of tablespoons an hour--not a lot).

I am wondering where the oil-sending unit would be for this model? It has been suggested that this could be the difficulty.

Thank you very much for your assistance!!
:grinno:

HTB