I've pasted the repair instructions below:
2003 Mercury Grand Marquis V8-4.6L VIN W
Vehicle » Lighting and Horns » Headlamp Switch » Service and Repair
SERVICE AND REPAIR
Remove the instrument cluster finish panel.
Unclip and remove the headlamp switch.
Remove the headlamp switch and bezel assembly.
Disconnect the electrical connectors.
CAUTION: Cover the end of the tool with tape to prevent damage to the trim panel.
NOTE: Use a thin blade tool to remove the headlamp switch bezel assembly.
Release the three tabs and remove the headlamp switch.
To install, reverse the removal procedure.