2004 Cadillac DeVille Owner's Manual - Page 336

6. Remove the bulb socket dust cover. 8. Pull the old bulb out of the socket. 7. Turn the headlamp housing socket counterclockwise to unlock the socket from the lamp housing. 9. Install the new bulb into the socket. Make sure that the bulb is locked in firmly. 10. Reinstall the headlamp housing socket into the headlamp assembly. 11. Reinstall the headlamp assembly by reversing Steps 2 through 6. 5-56