Where is the oil sending unit located on 1997 Chevy s10 blazer 4.3 v6?

The oil pressure sending unit on a 1997 Chevy S10 Blazer with the 4.3L V6 engine is located on the driver's side (left) of the engine block, near the oil filter. It's a relatively small, usually one-wire, sensor. You'll likely need to get under the vehicle to see it clearly.