Location of oil sending unit on a 1988 Chevy pickup c1500?

The oil sending unit on a 1988 Chevy C1500 is located on the passenger side of the engine block, usually near the oil filter. It's a small, cylindrical unit with one or two wires connected to it. However, the exact location can vary slightly depending on the engine (e.g., a 305 vs a 350).

To be certain, you should consult a repair manual specific to your truck's engine. A Chilton's or Haynes manual will have diagrams and detailed instructions. You can also search online for "1988 Chevy C1500 [engine size] oil sending unit location" to find images and potentially videos showing its location.