Cadillac 2004 DeVille - Manual (Page 335)

3. Loosen the bolt at the bottom of the headlamp
assembly.
4. Use a tool to help pry the headlamp assembly away
from the vehicle.
5. Firmly grasp the outboard side of the headlamp
assembly with both hands and pull hard enough
so that the whole assembly separates from
the vehicle.
5-55