Replacing a headlight in a 2003 Subaru Forester is simple enough; there is sufficient room behind the bulb to replace it without removing the entire assembly. Unfortunately, this is not the case when replacing the parking lights. The entire assembly must come out, and this requires a bit of time and patience: Expect the procedure to last 20 to 25 minutes. The process you'll undertake to replace the 2003 Subaru Forester car park is the same process you'd use for 2004 through 2008 Foresters.
Turn the engine off and open the bonnet. Look closely at the plastic grille insert (with the Subaru emblem) between the headlights. There are seven clips: four on top and one each on the sides.
Insert a flathead screwdriver onto each clip while simultaneously pulling the grille insert forward. This will release the clips from the Forester, allowing you to pull the front grille insert off.
Remove the two fasteners from the plastic panel on the inboard side of the headlight assembly. Pull them off with your hand or pry them up with a flathead screwdriver. Slide the plastic panel outward to expose the inboard headlight assembly mounting bolts.
Remove the two inboard mounting bolts with a socket wrench, then remove the last bolt on the outboard top corner of the headlight assembly. Carefully slide the headlight forward to access its rear. Be careful not to scratch the bumper cover. Unplug the electrical connections on the rear.
Twist the parking light bulb counterclockwise to remove it. The parking light bulb is the top lamp on the outboard side. Pull the old bulb straight away from the socket.
Insert the replacement bulb into the socket. It's imperative that you wear clean gloves, because it's impossible not to touch the bulb with your hands when replacing it. Touching the glass with your skin can damage the bulb. Reinsert the socket with the replacement bulb into the assembly. Twist it clockwise to secure it.
Reconnect the electrical connections to the rear of the headlight assembly. Reinsert the headlight assembly into the Forester. Tighten the three bolts.
Reposition the plastic cover on the inboard side of the headlight assembly. Reinsert the clips to secure it. Position the front grille insert back in place. Depress the tabs with the flathead screwdriver and firmly push the insert forward to reattach it.