Retrofitting projectors into a factory Subaru housing can look intimidating from the outside, but the Morimoto RetroQuik Subaru Impreza system is designed to take a lot of the guesswork out of the process. We spent time on the bench working through a complete install on a 2006-2013 Impreza / WRX headlight, and in this guide we walk you through exactly what we did, from mounting the side-specific projectors to sealing the ballast and finishing the wiring on the back of the housing. If you have been researching a Subaru Impreza headlight retrofit, this breakdown will show you how the whole kit comes together.
Getting Started With the RetroQuik Kit
The first thing worth noting is how much of the hard work is already done for you. The projectors that come with the kit are side specific, and they have a notch cut out of one of the top corners. In the example we worked on, this was the right side headlight, so the notch was cut out of the top left. The reason for that notch is simple: it lets the projector clear the aiming adjuster pivot point on the housing. That small detail matters, because a projector that fights against the aiming adjuster is a projector that will never sit correctly.
The brackets come pre-mounted on the projectors, which saves a big step. You install the projector from the back side of the bracket, and the mounting holes line up with the mounting holes from the original projector. We used the screws that came with the kit on the top bracket, threading them straight into the bracket, and on the bottom bracket we used the included nuts on the back side. Everything ties together nice and tight when it is done correctly. This is the same clean approach you will find across the WRX bi-xenon projector kit lineup.
Mounting the Matsushita Ballast
Once the projector is secure to the bracket, you go back to the main housing so you can mount the ballast onto the bottom. This is one of the details we really appreciated about the Subaru platform: even the halogen version of the WRX headlight has bosses built into the bottom of it for the OEM Matsushita ballast. That means you are not fabricating a mounting point from scratch, you are using what the housing already has.
When the ballast comes to you, the igniter cord (the mesh cord) is already attached. To get that off, you depress the little clip on the side and it pops out and unclips itself. There is also one small screw you have to undo, and you want to pay attention to which way it is going so you do not lose it, because it is small. Set the igniter aside for the moment.
Creating a Watertight Seal
The kit also comes with a rubber O-ring, and this is so the ballast can make a watertight seal with the bottom of the housing. You put the ballast igniter in from the top of the headlight through the hole, pass it through the bottom so it rests inside, and then you add the O-ring and put the plug back into the ballast. The holes should line up so they go into the three holes in the bottom of the housing, and you mount everything with the screws that come with the kit. Once the O-ring is in place and everything is screwed back in, it should be all set and sealed against moisture.
Reinstalling the Reflector Assembly
After the ballast is mounted, you can put your reflector assembly back into the housing. The first screw you want to put in is the one that comes out of the bottom of the ball joint type socket, the same spot you drilled the hole for earlier. We put that one in first because it is basically impossible to get to otherwise. Drop it in, then line up all of the aiming adjusters with their screws inside the headlight, and use a 6mm socket to tighten them back on.
Here is an important step that is easy to overlook. The cable for the bi-xenon solenoid needs to be passed over to the high beam side of the headlight before you screw this in all the way. Doing it now makes connecting it to the high beam circuit a lot easier later on. We passed it through so it came out the side that has the rubber grommet. Once that solenoid wire is routed, we screwed in the two aiming adjusters, put the bolt back in that we set earlier, and reinstalled the one at the top. At that point you should be good to go. If you want to cross-reference the process against the manufacturer material, the RetroQuik headlight install resources are a helpful companion.
Installing the Bi-Xenon Bulb
With the bulb holder back in place and the bi-xenon solenoid input routed to the high beam side, it is time to reassemble the back side of the housing. The bulb holder just threads onto the back of the projector. When you removed this part, you probably found two pieces that fell into the headlight: a metal O-ring and a rubber O-ring.
The bulb goes in first. As with any bulb, you want to make sure you clean it first so there are no contaminants on the glass. The metal O-ring goes on first; you slide it on and rotate it so it goes over the locking tabs for the ballast. The rubber piece has a chamfered side, and the angled (chamfer) side goes in first. You slide that on, pass it over the bulb, get it seated, and then put the cap back on with moderate pressure. You do not need to crank it down too tight. From there you tuck in the igniter, twist on the bulb, and the housing cap over on that side is ready to be reinstalled. The top cap twists on just like stock.
Wiring the Solenoid Connector
On the new projector you have the positive and ground for the bi-xenon solenoid. With the projector you get a plastic socket and two rubber seals. You install those parts onto the end: put the rubber grommets on first, pass them over the metal pins, and then clip them into the plastic socket. We like to use needle nose pliers to pull them through because it makes the job a lot easier. Once that is done, the original rubber boot you took off goes back on, with the wiring on the inside of it. Press it back around, and then reinstall the plastic cap that goes on the back.
Finishing the Back-Side Wiring
With the bulbs and seals in place, you can do all the wiring on the back side of the headlight housing. The first thing is to reinstall the input pigtail on the Matsushita ballast, which just clips in. This provides power to the ballast later and connects to the relay harness. Set the output that came with the kit aside for now.
Next is the high beam splitter, and this is where you want to pay attention. One side of the splitter has two stripes and one side has a single stripe. The side with two stripes goes to your original halogen high beam bulb. The side with one stripe goes to the bi-xenon solenoid connector that we poked out the back earlier. Leave the solenoid side dangling for now while you reinstall the bulbs and everything else on the back.
The original wiring for the halogen light bulb is not needed anymore, but it does not go to waste; it provides the input power for the relay harness because it is the H11 connector. We left that dangling for now as well. Then we remounted the main multi-pin connector on the back of the housing where it was removed before we opened the headlight. The last thing to do over on this side is hook up the halogen high beam bulb and the bi-xenon solenoid. You remove the original connector from the bulb, plug it into the splitter connector, and then plug that back into the bulb. Once that is done, all the wiring on the back side of the headlight is good to go. For more product background, the broader Morimoto catalog is a good place to explore what else is available.
Cleaning Up and Final Reassembly
With the rear side reassembled and all the wiring done, you can clean up the front. Make sure there is no dust anywhere inside, and make sure the front lens is clean and free of fingerprints. There is nothing worse than a fingerprint on your projector once you have the headlight resealed. We cleaned everything up, made sure it was solid, and then remounted the turn signal reflector, dropping it carefully over the bulb and lining up the two screws before tightening them down.
Finally, the front lens goes back on. We put some glue in between the junction, then reheated the housing all together and put it back together. That final baking step is what locks the whole assembly back up so it looks and seals like a factory unit.
Final Thoughts
What stood out to us during this install is how much thought went into making the RetroQuik system a bolt-in solution for the Subaru platform. The side-specific projectors with the notched top corner, the pre-mounted brackets that align with the OEM holes, the factory bosses for the Matsushita ballast, and the color-coded high beam splitter all combine to make a project that could otherwise be a headache feel manageable on the bench. Take your time with the O-rings and the wiring, keep the lens clean before you reseal, and you will end up with a sharp bi-xenon projector setup that fits your 2006-2013 Impreza / WRX headlights.
Frequently Asked Questions
What years does the Morimoto RetroQuik system fit?
The kit is built for 2006-2013 Subaru Impreza and WRX headlights, and even the halogen version of the WRX housing already has bosses for the OEM Matsushita ballast.
Are the RetroQuik projectors side specific?
Yes, each projector has a notch cut into one top corner so it clears the aiming adjuster pivot point, which makes the left and right projectors different parts.
How does the ballast attach to the headlight housing?
The Matsushita ballast mounts to the bottom of the housing through the factory bosses, seals with a rubber O-ring for a watertight fit, and is secured with the screws included in the kit.
What does the high beam splitter wire do?
The splitter has one side with two stripes that connects to the original halogen high beam bulb and one side with a single stripe that connects to the bi-xenon solenoid connector.
How is the new bulb sealed inside the projector?
After cleaning the bulb, a metal O-ring is slid on first and rotated over the ballast locking tabs, then a rubber O-ring with its chamfered side facing in is added before the cap is twisted on with moderate pressure.
Meet the Experts Behind The Retrofit Source
Tyler Jordan – Technical Writer
Tyler works directly with the TRS product R&D team, bringing over a decade of automotive aftermarket lighting experience to every article. An avid enthusiast with hundreds of personal installations under his belt, his content is built on hands-on knowledge from the workbench, not spec sheets.
Caleb Morgan – Marketing Manager
Caleb brings over a decade of automotive lighting industry experience and works with TRS customers daily on the front lines. With hundreds of personal lighting installations and a direct feedback loop from real buyers, his content addresses the questions and problems that actually matter.
