Subaru IMPREZA 2002 Owner's Manual page 385

Maintenance and service
3. Remove three bolts and disconnect connectors,
and then detach headlight assembly.
11-60
HGB030BA
HGB031BA
4. Remove the bulb socket from the headlight as-
sembly by turning it counterclockwise.
5. Pull the bulb out of the socket. Install a new bulb.
6. Set the bulb socket into the headlight assembly
and turn it clockwise until it locks.
HGB010BA