The 2004 Toyota Celica uses halogen bulbs for increased visibility. Though halogen bulbs have a longer life than standard sealed headlights, halogen bulbs will eventually burn out. Replacement will only take a couple of minutes, as there is no tools required for this task. Always replace the bulb immediately for optimum visibility.
Open the Celica's hood to access the back of the headlight assembly. Determine which headlight is faulty, and locate the back of the faulty headlight.
Pull the wiring off the back of the headlight bulb socket by squeezing the tab and separating the wiring from the socket. Twist the socket counterclockwise and pull it away from the headlight assembly. Discard it.
Twist the new bulb and socket into the assembly clockwise. The socket will lock in place.
Push the wiring on to the socket. The wiring will lock once it is pushed on far enough.
Test the headlights to ensure they are functioning properly. Close the hood when done.
The 2004 Toyota Celica GT's low-beam part number is H-7; its high-beam part number is 9005. The Toyota Celica GTS's low-beam part number is HID-D25. The GTS's high-beam part number is 9005, the same as the GT high beam.
Do not touch the glass portion of the bulb/socket, as the oils on your skin can cause the bulb to overheat and burn the bulb out prematurely.