How do I change a headlight lamp in a 2004 Toyota Celica?

Changing headlight bulbs in the Toyota Celica is similar to replacing bulbs in other cars, and may actually be easier, since Celica models have headlight compartments that are easy to reach and access. You will probably spend most of your time choosing the proper bulb for replacement, since exchanging the headlights themselves is a simple process.

Preparation Steps

First you must make sure that you have the right bulbs to replace your old lamps. If you want to get the same type of headlights, try to find your serial number and look up the bulbs on an official Toyota parts provider website. Different Celica models have different sizes of headlight bulbs, so you cannot simply choose any Celica bulb available. Many sites will give you a list of bulb requirements depending on your model, with separate sizes for low beam and high beam lights. This information is especially important if you want to switch your headlight lamps to a newer model, such as LED-based bulbs or another version.

When you have the replacement bulbs and are ready to make the exchange, move your car into a dry area where you can easily access the hood. Have both bulbs at hand, and be sure to wear goggles when you begin. Some types of halogen bulbs may pose an explosion danger due to their pressurized gas, and goggles will protect your eyes in case of an accident.

Replacing the Headlight Lamp

Open your hood and look inside the engine compartment. On the inside of your Celica there should be what is known as a headlight assembly, or an access panel at either corner which opens directly to the headlight compartment. This shows the back of your current bulbs. These use a screw or twist-lock mechanism known as retaining rings that must be unscrewed before you can remove the bulb. Remove the bulb base by wiggling it back and forth until it becomes dislodged. You will then need to remove the wiring harness from the back of the bulb (the wires are designed to slide in and out of the bulb's base).

Carefully remove the old bulb from the car, then replace it with the new bulb by reversing the steps, making sure that the wiring harness is connected in its upright position and the retaining rings are put back in place. If you get a more advanced headlight, there may be separate fasteners you will also have to include.

Source:

Automedia: Changing Broken or Burned-Out Lamps