How do you change brake light bulb on a 2000 Saab 9 5 station wagon?

When you open the back hatch, you'll see two penny-sized black plastic caps near the brake light. They are on the rear-facing lip that is ordinarily covered by the closed hatch, between the rubber seal and the brake light. Pry those off, and you'll see screws. To remove the screws, you'll need the original tool kit that came with your Saab, because the screws take a six-sided star screwdriver (not a standard hex/allen screwdriver). Once the two screws are removed, pry the tail light assembly out to the side. If it's the driver-side brake light, pry left, for the passenger pry right, because there are metal pins holding the tail light assembly onto the side of the car, and you don't want to break those pins by pulling straight back toward the rear of the car. The brake lights, on the body of the car, take P21/5W bulbs, and the tail lights, on the hatch, take P21. The two are NOT interchangeable...Put a P21/5W in the hatch and it will eventually melt the plastic; put a P21 in the brake and it will be too dim.