I replaced my HID (Xenon) bulbs yesterday. The process is not complicated, but here is a mini write-up anyway:
Warning: HID Xenon bulbs operate at a very high voltage (in the neighborhood of 35,000 volts if I am not mistaken).
This voltage is generated by the ballast. As always, when working with anything electrical on your car, it might not be a bad idea to wear gloves and to disconnect your battery’s negative terminal. There may not be any voltage stored in the actual ballast. But as they say, “living is better than dying.” So please be careful. If you are uncomfortable with this in any way, seek the help of a knowledgeable friend or professional. Always be safe 🙂
Headlight beam pattern with D2S bulbs. D2S bulbs do not have the ceramic paint coating that D2R bulbs have. D2S bulbs are designed for projector headlights while D2R bulbs are designed for projector headlights. the 2004-2005 WRX STI uses reflector headlights. WRX headlight reflectors are not the same shape as WRX STI reflectors, so do not use HID bulbs of any kind in a standard WRX headlight. If you see them side-by-side, the differences in the shape of the reflector ‘bowl’ are visible.
Headlight pattern with D2R bulbs. D2R bulbs are half-painted with ceramic paint to prevent light from reflecting off of the bottom of the reflector housing inside the headlight. This limits the amount of light that will shine upward into eyes of oncoming drivers. While the photos are not the best and were not taken with identical camera settings, the D2S photo has more upward light scatter than the D2R. The D2R is the correct bulb for the 2004 and 2005 WRX STI headlights.
In the picture below, you can see the D2S bulbs on the left, and the D2R bulbs on the right. Notice the brown ceramic paint covering part of the glass on the D2R to limit light output in one direction.
D2S and D2R bulbs side by side
To get started with the actual replacement:
1. Open your hood and prop it up.
2. Unbolt your air intake duct if you are using the stock OEM intake system, pictured below. They are likely 10mm bolts. Give the intake duct a pull to the right, and it will pop off of the connector elbow the runs through the fender well.
3. Remove the grille by pushing down gently on the plastic tabs that protrude through the grille from the upper radiator support cross-piece. My bottom clips were already broken off, so you may need to find a way to carefully release these as well if you still cannot remove the grille. The grille should pull straight out forward with slight wiggling.
4. Remove the plastic pop fasteners. Two are next to each headlight, and there are several that attach the top of the bumper to the metal frame of the car. Use a flat-bladed screwdriver inserted into the notched area of the clips. Pry gently and the top screw-like part will rise up. You don’t need to remove it all the way, just loosen it and pull the whole fastener out.
Below is a photo with the grille removed. You can see the hood release mechanism as well as the round horn transducers.
5. Directly underneath the plastic fasteners near the headlight that we just removed, you will see a white plastic piece bolted into the frame. This should also be a 10mm bolt. I like to use a ratcheting box-wrench to loosen and remove this. Sometimes it catches and will not come out easily. Be careful and take your time so that you don’t crack the white plastic part. They can easily be broken if you apply too much force.
6. Remove the two 10mm screws attaching the top of the headlight to the metal frame, and you should now be able to pull the headlight forward with a firm pull. There are two ball-and-socket connectors attaching the outer part of the headlight into the fender. You may have to give these a very firm pull to pop them out. I recommend freeing up the white plastic clip first, and then pulling out the ball/socket side afterward.
7. Wiggle the assembly and pull back the bumper plastic slightly above the white plastic piece to ease out the headlight housing. You should be able to pull it out about this far, depending how long your wires are.
8. the round cover with the HID sticker and warning label and you will see the back of the HID Xenon bulb with the igniter attached.
9. the igniter by twisting a partial turn (as if you were unscrewing a screw). It will pop off if you pull it straight backward off of the bulb.
10. Depress the spring clips, one at a time, and push them slightly sideways to un-hook them. The spring clip will life up and you can now remove the bulb carefully. Try not to touch the glass, so as not to leave oils from your skin on the glass. On a traditional halogen bulb, skin oils will cause the glass to heat unevenly and can cause them to burst when the bulbs heat up.
11. Now insert your new or replacement bulbs and follow the above steps in reverse to put everything back together. I recommend testing the bulbs to make sure they work and to make sure all of your electrical connections are functional, before you put everything back together.
12. Enjoy your new or functioning headlights 🙂