However, the exact location can vary slightly depending on the engine (3.1L, 3.8L). A detailed diagram in a repair manual specific to your Grand Prix's engine is the best way to be certain. You can often find these manuals online (e.g., Haynes or Chilton) or at auto parts stores. You could also use a reliable online parts catalog like AutoZone or Advance Auto Parts and enter your vehicle's information to find a diagram.
Caution: Always disconnect the negative battery terminal before attempting any work near the engine.