May 21, 2018

Morimoto D2S 4.0 HID Retrofit

44 MIN READ

wrx , guides

As I lay on the ground searching the undertray for the washer I’d dropped into the WRX’s engine bay, I began to wonder if the all the work I had already put into my HID retrofit had been worth it. After four days worth of undoing and redoing pop clips, bolts, screws, rubber sealant, spray paint, dremeling, and Lyfts to the hardware store, I had reason to question my sanity!

I’d eventually come to appreciate the fruits of my labor when I fired up the HIDs for the first time, but to say the project had been “challenging” would be an understatement. Fortunately, the final result is a lighting setup that wipes the floor with the stock halogen system. For the money, it’s an incredible value and, while I haven’t had a chance to directly compare the two, I’m pretty confident the Morimoto system either matches or exceeds the factory LED system in terms of performance.

Background

In researching this project, I quickly grew frustrated by the lack of detail/pictures in a number of important areas. There’s a ton of great videos and forum threads discussing HID retrofits for the WRX, but thanks to broken links and images (screw you Photobucket), incomplete documentation, or vague descriptions, I still felt a little unprepared and anxious about the process.

With this in mind, I’ve assembled (what I hope is) a thorough guide to retrofitting the 2015+ WRX with the Morimoto D2S 4.0 bixenon projectors. When considering the time required for this project, please keep in mind that documenting everything with detailed pictures and step-by-step notes took a good amount of extra effort and added hours to the overall process for me. That being said, it’s not a project for the faint hearted. Depending on whether or not you paint the housings or add aftermarket c-lights, you’ll need at least two to three days to get everything done.

If all that sounds intimidating, don’t be discouraged - I’ll break things down step-by-step! I hope this guide is able to give you a better idea of what you’re in for and serve as a reference as you retrofit your own headlights!

First things first: Let’s explore everything you’ll need to do this yourself.

Choosing The Parts

There are a few options available for the 2015+ WRX as far as HID retrofit systems go, but (as of writing) the main two are the Morimoto Mini H1 7.0 and Mini D2S 4.0. Both have “plug-and-play” kits available from a variety of companies, and both are respectable options for a retrofit. That being said, the D2S 4.0 system is newer and arguably performs better than the H1 7.0. See the below video from Lightwerkz comparing the output of both projectors:

As you can see, the D2S 4.0 has a brighter, higher intensity output. The projector itself is larger, which can cause problems for retrofits in smaller headlights. However, it’s a non-issue when replacing the 2015+ WRX low beam halogen projector as the D2S 4.0 fits perfectly (with minor adjustments to the housing that I’ll highlight later).

D2S projector

Because of this, I opted for the D2S 4.0 Retro-Quick kit from Lightwerkz. I chose to order from Lightwerkz for a number of reasons, but mainly because I had referenced many of their videos highlighting their 2015+ WRX retrofits and their customer service. Caesar and his team do awesome work, and their willingness to help out and answer questions really impressed me. At a number of important points in my build, I called them up and had an answer and/or resolution to a problem within a few minutes.

Below is a detailed list of the options I went with (with some adjustments per my findings) for the Retro-Quick kit from Lightwerkz:

  • Bixenon Projectors: D2S 4.0 (LHD) (USA & CAN)
  • Mounting Hardware: 15+ Impreza
  • Compatible Ballasts: Morimoto XB35 (35W)
  • HID Bulbs: D2S: XB HID 5500K
  • High Beam Splitters (Pair): 9005 Female > 9005/9006 Male Splitters
  • Wiring Harness: HD Relay: H11/H9/H8
  • Headlight Sealant: Black RetroRubber
  • Rubber Caps: No

Regarding my choices:

  • The mounting hardware includes a set of machined adapter plates for attaching the D2S projectors using the OEM projector mounts. Because there weren’t any instructions included, this part required a little trial and error - I’ll go into detail here later on, but rest assured the adapter plates work great!
  • I went with the 35W ballasts over the 55W for reliability and longevity. I had read the 55W ballasts can generate more heat and wear out the other components faster.
  • In my research, I found that the Morimoto XB 5500K D2S HID bulbs provide the whitest output; 4500K may be “truer” white, but 5500K has less of a yellow tint. After running the lights for a few weeks now, I am very satisifed with the temperature output of the 5500K bulbs. If I had the budget, I’d have opted for the Osram 5500K bulbs as they appear to be better both in terms of reliability and performance.
  • The high beam splitter(s) are not necessary unless you plan to retain the stock high beam bowl. I hadn’t decided whether or not I wanted to black my high beam bowls out at the time of ordering, so I picked up a set to be safe.
  • Headlight sealant - some people will say the factory headlight sealant is reusable, but I did not find this to be the case. As I’ll explain a bit later, the OEM sealant was by far and away the most frustrating part of the build for me. Just spend the few bucks and pick up the RetroRubber.
  • Rubber caps - I added these to my order with the understanding that they’d be necessary as the OEM covers wouldn’t be compatible with the new D2S projectors. However, after much trial and error, I wasn’t able to find a way to reliably secure these aftermarket caps and ended up finding a solution that reused the factory covers instead. These can be skipped.

In addition to the Retro-Quick kit, I picked up the following items:

  • Diode Dynamics C-Lights: I went with the Diode Dynamics c-lights over the Morimoto for a number of reasons, but mainly due to their whiter output, reliability, and excellent build quality.
  • Diode Dynamics C-Light DRL Harness: Since I’m using the c-light as my DRL, the DRL harness allows me to bypass the factory DRL (actually the high beam in low output) and have the c-lights on at all times. After a few weeks of running the harness, I actually disconnected it; I prefer to have the option of turning the DRLs on/off rather than them coming on automatically when the handbrake is off.
  • Smoked Sidemarkers: If you want to get rid of the orange sidemarker, Subispeed sells drop-in replacement lenses in both clear and smoked varieties. You can also try tinting the OEM sidemarker, but it’s much easier to just replace them altogether.

Other parts needed:

  • (100) #8 Flat Washers: You’ll need quite a few of these, so grab yourself a box of 100. These are used for spacing and leveling the new D2S projectors on the headlight frame, as well as mounting the ballasts and other hardware in the engine bay.
  • (10) #8 bolts and nuts (3/4 in): These will be used with the washers to mount the HID harnesses/hardware in the engine bay. I picked up a “combo pack” of machine screws and nuts.
  • (1) Rust-Oleum Grey Plastic Primer: While the Krylon Plastic spray paint doesn’t explicitly require a primer, I felt it wouldn’t hurt. After forgetting to prime a few pieces, I can confirm the primer does make a difference.
  • (1) Krylon Fusion Satin Black Plastic Paint: I ordered a few cans off Amazon, but I believe this stuff is available in most hardware stores as well. I went with satin as that’s what Lightwerkz and other guys have been using. I contemplated gloss, but am happy with the satin look. I ended up using a little over half a can, but you may want to get a couple just to be safe.
  • (1) Rust-Oleum Frosted Glass: I used this to add a bit more diffusion to the factory c-light lens. It added a bit more “pop” to the lenses and contrasts against the black housing nicely. Maybe not everyone’s cup of tea, but worth it in my opinion.
  • GE 100% Waterproof Silicone: This will be needed to seal up any unused holes in the headlight as well as secure the OEM rubber caps to the back of the new projectors. Any waterproof silicone should do fine.
  • Painters Tape: Very helpful for masking off the c-light area if you want to keep the chrome reflectivity of the light. One roll is plenty.
  • 22-18 Gauge Quick Disconnects: These aren’t explicitly necessary, but I found a few of the male connectors on the provided harnesses to have a poor connection, causing a short in the Diode Dynamics c-lights so I replaced them all and soldered. I’ll go into more detail on this later.
  • Ziploc bags: There’s quite a few bolts, clips, etc. you’ll need to store. I put each set into their own labeled bag, making reinstallation much less of a headache.
  • Trim/Fastener Removal Tool: This was a last minute pickup that saved me a ton of headache and made the whole process so much smoother - I highly recommend!

All in, I believe the cost of all the parts and supplies came out to around $600 shipped ($550 for the HID kit and c-lights, $50 for the supplies/misc stuff). At the time of writing, using the discount code “JUNKIE” at Lightwerkz should apply a 10% discount!

With everything ordered, Lightwerkz had everything shipped in a few days! Upon receiving the package, I opened and laid everything out to verify nothing was missing.

Everything needed for the retrofit (almost)

I highly recommend this step as I quickly realized I had been sent a wrong igniter. One quick phone call later, Lightwerkz had a replacement in the mail.

Small rant: My one and only complaint regarding my experience with Lightwerkz would be that they used USPS Ground for shipping the replacement/RMA parts, which meant I had to wait over three days for the correct igniter to arrive. Having only one igniter didn’t prevent me from finishing the project, but did make it signficantly more frustrating to get everything mounted and aligned (I had to swap the single igniter back and forth between the headlights).

These slight hiccups aside, everything arrived well packaged and ready to use.

Preparation

Prior to doing any work, I parked my car in the garage and positioned the headlights as far away from the back wall as possible to mark the OEM cutoff position with some tape. I’ve read that 25’ away is the sweet spot for alignment, but that wasn’t realistic for my situation. Instead, I decided to simply mark the cutoff points at that distance and use that as a baseline for aligning the new projectors later on.

Marking the OEM alignment

Next, I prepared to remove the front bumper by popping the hood. There’s no need to jack up the car, but you will need to get underneath to access a few pop clips. There’s six 10mm bolts and three pop clips up top, two push clips (one in each) in the fenders, and nine pop clips on the bottom side of the bumper. Once you have all of the bolts and clips removed, gently pry the bumper away from the fenders first then up and away from the bottom. You’ll need to unclip the fog light/turn signal harness before you’re able to completely remove the bumper and set it aside.

Top of bumper clips/bolts

Fender push clips

Bottom of bumper clips

Bumper removed

Next you’ll need to remove the plastic shrouds holding in the headlights - four 10mm bolts and one pop clip each.

Front of headlight shroud

Side of headlight shroud

For the headlights themselves, there’s two 10mm bolts and a single pop clip holding them to the frame. Once you get the headlight off, you can unplug the various bulbs, gaskets, wires, etc., but I found it easiest to unscrew the main bracket rather than struggle with the big grey plug itself.

Headlight bolts and clip

Headlight unbolted

Headlight plug bracket

Bulb #1

Bulb #2

Bulb #3

Bulb #4

There are six phillips head screws holding the headlight housings to their lenses which will need to be removed prior to splitting them open. In addition, you can remove the caps on the alignment bolts and set these aside - I opted to leave these off permanently for easier access to the alignment bolts later.

Back of headlight

With the headlights uninstalled and all the bulbs and hardware disconnected, it’s time to get them split open!

OEM headlights removed

Splitting Up

Prior to starting this process, I had read a number of forum posts/watched a few videos stating that it wasn’t necessary to bake the headlights in order to separate them. These individuals either have hurculean strength or their headlights’ had significantly weaker sealant than mine, because I had a HELL of a time getting mine apart. Even after baking them in the oven at 200 degrees for a few minutes to soften the butyl, I had to resort to a combination of brute force and slicing through the butyl with screwdrivers to get them separated. I found starting at one corner and working my around with a few screwdrivers worked best.

Baking the headlights

Splitting the headlights

Headlights split

Eventually the headlight lenses and housings should separate.

Now, even if you managed to keep the OEM butyl in good condition, I’d HIGHLY recommend removing it all at this point. In the following steps it would be a nightmare to try and keep things from sticking together, and using a new seal of RetroRubber later is the best idea to prevent any leaks anyways.

Disassembly/Masking

With the lens separated from the housing, you can remove the three screws holding the chrome bezel to the plastic lens. I opted to put the screws back in the lens for safe keeping. You’ll now have access to remove both the orange sidemarkers and c-light lenses.

Bezel screws

Bezel screws

Screw in lens for safe keeping

OEM sidemarker

The sidemarkers should pop off with a little pressure on the clips inside, but the c-light lenses are a bit trickier.

Removing sidemarker

Sidemarker removed

The c-lights are anchored in five locations, so I’d recommend starting on edge and pinching the upper and lower clips to put some outward pressure on the lens itself. Eventually you should have enough clearance to unclip the anchors in each of the “points” of the c-light, but just be careful not to pry or pull too hard; the plastic is pretty fragile.

Removing c-light lens

Removing c-light lens

C-light removed

Eventually the lens will pop out and you can begin to mask things off in preparation for the paint. I chose to keep the inner c-light lens chrome, as it allows for more reflectivity and contributes to a wider c-light appearance. This can be accomplished by masking off the c-light lens itself and reinstalling.

C-light masked

C-light masked

The headlight housing holding the projector and high beam bucket in place can be uninstalled a few ways. I opted to simply loosen the adjustments screws until the housing separated, but smarter individuals have noted you should mark (on the adjustment bolt’s threading) where the OEM alignment points are. This makes reinstallation and adjustment later on MUCH easier. Hindsight is 20/20…

Alignment bolts to be loosened

High beam bucket uninstalled

Painting

With both c-lights masked and reinstalled, it’s time to throw down a layer of the primer. This should have complete coverage in a few passes, and I let it cure for about 15-20 minutes between coats.

Primer can

Primer applied

Primer applied

Once the primer is dry, we’re ready for the black!

Paint can

I’d recommend many light coats with the black paint; too thick of a coat and it will quickly run. Be patient and allow a good amount of time (10-15 minutes) between coats. Depending on ambient temperature, you might want to use a heat gun on low to help speed up the curing process.

Paint closeup

Paint closeup

At this point you’ll want to decide whether or not you want to black out the OEM high beam reflector. Since the D2S 4.0’s are a bixenon unit (low and high in a single projector), the OEM high beam is technically redundant. Since I was going for a full blackout look, I decided to try a few different techniques to maintain the OEM reflector. However, after a few failed attempts with Duplicolor’s Shadow Chrome kit, I started from scratch and just blacked the high beams out with the same satin paint as the bezel. I had originally planned to attempt a quad HID retrofit, installing a second set of Mini H1 7.0 projectors in the high beam bowl, but it was out my budget for this project. With the high beam bowl blacked out already however, re-opening the headlights and retrofitting the second set of projectors will be a much easier process and could be a fun project down the road!

Regardless, if you decide to black out your high beams, you may want to mask off the rest of the bracket/housing to prevent overspray (if your OEM projectors are still in place). Technically it can all be blacked out, but you don’t see any of the chrome behind the bezel anyways. If I was going to do it over, I’d just remove the OEM projector first and hit it all at once, but since I’d been experimenting with tint I had it masked off.

High beam masked

High beam painted

Once you’ve finished your last coat of black (I did four), it’s best to let the pieces sit and cure overnight. This will help mitigate any chipping/peeling as you work with the painted pieces in the next steps.

With the black paint dried, you can remove the masked c-lights. This should be a delicate process, as there’s a high chance of messing up the clean black finish you just laid down. Start with the edges of the c-light as before and work your way towards the pointed tips slowly and carefully. Once you’ve got the masking off, take a minute to inspect your work for any chips, smudges, or other imperfections.

Removing masking

Removing masking

Touch up where necessary. If any paint made its way onto a surface it shouldn’t have, you can use a paper towel and a small amount of nail polish remover/acetone to very carefully remove it.

Chipped paint

While the chrome bowl of the c-light housing does a great job reflecting the light, I was looking for a more diffused look.

Unfrosted c-light

Inspired by the frosted white look of the Subispeed LED headlights, I picked up a can of Krylon Frosted Glass. After unmasking the c-light lenses, I took some time to cover and mask the outer side of the plastic in preparation for coating the inside with the Frosted Glass spray. This stuff can go on a bit heavier than the black paint, but be sure to avoid runs as before. I did about four wet coats before I decided it was as “frosted” as it was going to get.

Frosted paint

Frosted paint applied

Frosted c-light installed

The result isn’t quite as dramatic or opaque as the Subispeed lights, but it certainly adds some more contrast to the c-lights against the black finish of the headlight housing.

With the painting completed and the c-light lenses drying, I decided to move on to wiring up and testing the Diode Dynamics c-lights.

Diode Dynamics C-Lights

The Diode Dynamics c-lights come with excellent illustrated instructions, and there’s loads of detailed YouTube videos highlighting the install process as well. Because of this, I won’t be going over the wiring in detail.

C-light wiring

C-light harness

T-taps

One thing I noted was that the included t-taps create a pretty solid connection, but be sure you’ve got a needle nose pliers on hand to ensure they clamp completely closed. I found that one of the male plugs on the harness had a loose connection that would cause the c-light to cut out if it was wiggled, so I used some of the 22-18 gauge quick disconnects I picked up to replace the connector which fixed the issue. I continued to have shorting issues and had to pull the bumper back off and do the rest, so just I’d recommend doing them all at once. I’ve had no issues since redoing the all the connectors.

C-light wiring redo

C-light wiring redo

C-light wiring redo

If you opted for the DRL harness, be sure to get that wired up as well. The instructions for the DRL harness note you can leave the OEM resistor in place, but I removed it altogether - a decision which paid dividends later when it came time to wire up the HIDs!

DRL harness wiring

DRL harness wiring

DRL harness wiring

DRL resistor before

DRL resistor after

As for mounting/securing the resistors for the DRLs, I used double sided tape and a few exposed portions of the car’s frame:

DRL resistor mounting

With the c-lights wired up, be sure to test them out. You’ll have to pull your bumper back over to the car in order to tap into the turn signals as well.

Testing the c-lights

If everything works, you’re ready to install the c-lights into the headlights! Simply disconnect the c-lights from the rest of the wiring and feed the connector through the OEM c-light hole (located in the top corner of the bezel). I had assumed I’d need to find a way to secure the c-light boards to the headlight housing, but with the lenses re-installed, there’s no chance of them wiggling around.

C-light reinstall

C-light reinstall

C-light reinstall

Your frosted lenses should be dry by now, so carefully re-install them into the headlight bezel. It gets a bit tight towards the edges of the c-light, but everything should fit back together. I had a little trouble getting the far ends of the bottom of the c-light lenses to re-insert, but they held in place just fine so I didn’t fuss too much over it.

C-light reinstall

Be sure to reinstall your sidemarkers as well.

Sidemarker reinstall

Sidemarker reinstall

Now it’s time to move onto the actual retrofit!

Retrofitting the D2S Projectors

Having done a decent amount of research on retrofitting prior to starting the project, I felt reasonably well prepared for this part. Unfortunately, because the Lightwerkz kit didn’t come with any directions, I had to resort to a mixture of scouring forum threads, YouTube videos, and old fashioned trial-and-error. The good news is that it isn’t all that complicated! You just need to know the order of steps to follow and make sure you’ve got the right tools on-hand before you start.

With that in mind, I’d highly recommend having a Dremel or other rotary tool on-hand to modify the OEM housing. Technically you could probably get away with a few round files and sandpaper, but it’s going to be much easier and precise to use a Dremel.

First step is to lay out all of the parts from the D2S 4.0 kit (both projectors and the included brackets):

  • Two D2S 4.0 projectors
  • Two HID bulbs
  • Four c-shaped brackets
  • Eight allen bolts and lock nuts
  • Two springs
  • Two high beam cables and plastic connector housings
  • Two silicone gaskets
  • Two three pronged washer thingys
  • Two ribbed end cap bolts thingys
  • Two lock bolt thingys

D2S projector parts

Laugh if you want but I have no idea what to call the last three items. Just be sure to consult the picture above for reference.

Now before going any further, I’d recommend testing out the high beam switches on the projectors. You can do so by connecting the included wiring to the back of the D2S projector and touching each of the wires to the terminals on a 9V battery until you hear a “click” and see the shield flip. Supposedly it’s recommended to do this at least a few dozen times, but I got bored after 20 or so. Once you’re confident they are functioning correctly, you can insert the high beam pins into the included plug.

Assembling the high beam plug

Assembling

If you aren’t hearing/seeing the shield moving, double check the pins on the projector - one of mine had a bent pin that wasn’t seating correctly in the plug!

High beam wiring

Before fitting the new projector, you’ll need to unscrew the OEM projector. There are four screws holding it in place.

OEM projector screws

With the OEM projector removed, you can fit the included retrofit brackets and secure them with the four screws you just removed from the OEM projector. If I remember correctly, you may need to trim a little material off the top to get them to sit flush with the back of the housing.

D2S brackets mounted

Like any proud male without instructions, the first thing I tried was just jamming the new D2S projector into the OEM housing. Needless to say, there were most definitely some clearance issues to be sorted out.

Test fit #1

First, I trimmed the lower lip off completely. It serves no functional purpose for the retrofitted projector.

Marking where to trim

Trim complete

Again, I tried fitting the projector.

Test fit #2

More trimming was needed. This time I broke out the rounded grinding bit on the Dremel and sanded away some of the plastic on the bottom lip and corners.

More trimming

More trimming

Closer, but there were still clearance issues near the top and bottom corners.

Test fit #3

Test fit #3

Finally I was able to get the new projector inserted and aligned with the retrofit bracket mounting holes. Unfortunately, there was very clearly some interference from the D2S projector’s hardware and the screws holding the brackets in place.

Projector not sitting flush

At this point, I consulted Lightwerkz YouTube videos and discovered I needed some #8 washers to help space and level the new projector onto the housing. Unfortunately my car’s face was completely disassembled so I grabbed a Lyft to the nearest hardware store for a box.

#8 washers

Next came the fun of trying to figure out how to mount the included allen bolts in the retrofit bracket so that they A) sit straight and B) are accessible to be tightened after the projector is mounted.

Testing bolt alignment

Testing bolt alignment

I discovered that the housing would need to be trimmed/modified to allow the allen bolt head to be positioned flush behind the retrofit bracket. More Dremeling then!

Clearance for the bolts

Clearance for the bolts

Clearance for the bolts

Clearance for the bolts

Clearance for the bolts

Clearance for the bolts

With the clearances made, I drilled a pair of holes through the housing to access the allen bolts from the front side, as they’d be completely inaccessible once mounted behind the brackets. I then un-mounted the brackets and fed the bolts through the holes finally reattaching the brackets and threading on four #8 washers on the top two bolts and two on the bottom. Per Lightwerkz, this allows the projector to be more closely aligned to OEM specs before any adjustments are made with the headlight screws themselves.

Holes for accessing for the bolts

Holes for accessing for the bolts

Brackets mounted with washers

Brackets mounted with washers

Before threading the D2S projectors onto the bolts, I realized there was some flashing/casting blocking the bolts from threading nicely through the projectors. A combination of drill bits and dremeling opened these up enough to fit the bolts through.

D2S casting/flashing

Next, I removed two of the bottom-most phillips head screws from the front side of D2S projector to avoid interference with the retrofit bracket screws (after consulting the Lightwerkz video again).

Projector still not sitting flush

Two D2S screws to remove

Finally I secured the projector to the housing and bolts using a final #8 washer between the projector and included lock nuts. I tightened everything down one bolt at a time, taking care to close up the gaps between everything. Be sure to give it a once over to make sure everything is level both horizontally and vertically.

Projectors positioned correctly

Threading the lock nuts on

Access to the bolts

Everything tightened down

At this point the D2S projector is fully mounted to the OEM housing. Huzzah! Now it’s time to install and secure the bulbs for testing and alignment.

First you’ll need to carefully unbox your bulbs - I’d recommend doing this one at a time to prevent any damage to the bulbs; they’re fragile! Be sure not to touch the glass of the bulb.

Removing the bulb from the box

Next, gently insert the bulb into the back side of the D2S projector, return wire (the straight colored one) facing downwards. There should be a notch at the top of the opening on the rear of the projector and in the D2S bulb itself - be sure to align these.

Seating the bulb

Bulb seated

Next, grab one of the included springs I mentioned earlier and fit it over the end of the bulb. It should slide over the two pegs on either side of the bulb, but you will need to keep pressure on it to keep it falling off for now.

Fitting the spring on the bulb

Fitting the spring on the bulb

Now comes the tricky part. Using one of the “ribbed end cap thingys”, keep the spring on the bulb and slide the threaded cap over everything til it makes contacts with the threads on the projector. At this point you’ll need to continue applying pressure to keep the spring in place while rotating the cap clockwise to secure everything together. It may be hard to get it started with the pressure of the spring resisting you, so be careful not to cross thread it. Eventually though you should be able to tighten everything down by hand.

Threading the cap on

NOTE: At this point it doesn’t pay to tackle the gaskets quite yet, as you’ll be removing the bulbs prior to baking the headlight for re-sealing.

With the bulbs installed, let’s move on to getting the wiring ready for installing the headlights on the car itself!

HID Wiring

So far we’ve:

  • Painted the headlight bezels
  • Frosted the c-light lenses
  • Installed and wired the Diode Dynamics c-lights
  • Retrofitted the D2S projectors and installed the bulbs

Before we reassemble the headlights, it’s best to tackle the HID wiring. This will mean everything is prepared for the headlights when it comes time to make adjustments and level the new D2S projectors. For starters, lay out all of the items included with the Retro-Quick kit as well as some of the hardware we’ll need to mount everything:

  • Two ballasts
  • Two high beam splitters (optional)
  • HD relay wiring harness
  • Two D2 output igniters (I was sent an AMP igniter on accident)
  • /#8 bolts and nuts (3/4 in) (I got a ten pack)
  • /#8 washers

Pictured below is a rough idea of how the wiring will work (minus a second igniter).

HID wiring mockup

It’s pretty straightforward, but basically the wiring harness will be mounted on the passenger’s side with three of the wires running over to the driver’s side. Two of the driver’s side wires (labeled accordingly) will be used to connect to the vehicle’s positive battery terminal and a ground point on the frame. Instead of using a driver’s side ground, I kept this cable on the passenger side and wired it directly into the frame using the hole leftover from the OEM DRL resistor (see below).

Grounding point on passenger side

The other wire for the driver’s side will connect to the ballast there, which we will mount shortly.

The first thing I did was take the HID ballasts and bend one of the bracket arms so that they could be attached to the frame of the car with the plugs facing downward. I did the same thing with the bracket for the harness.

Ballast bracket arm bent

Harness bracket arm bending

Using one of the #8 bolts and nuts along with a pair of the #8 washers I had leftover from the projector mounting, I secured one of the ballasts and bracket into an open hole in the frame behind the passenger side headlight. For easier access, I removed the intake snorkel (two pop clips and it slides right out).

Removing the snorkel

Harness and ballast mounted

As you can see in the picture above, I mounted the bracket for the harness into a hole used by an OEM harness - I just popped the plastic connector out of the hole in the frame and secured it with the same bolt, nut, and washer combo as the ballast bracket.

For the driver’s side ballast, I mirrored the setup from the passenger side by utilizing a hole already in the frame. Apparently I didn’t get a good picture of this - most likely because I was close to delerium and/or sick of taking pictures. Sorry ‘bout that.

Regardless, it’s time to start plugging things in! First, the wire with the plug we sent over to the driver’s side can be inserted into the ballast there. While the ballast has two plugs, they have different mounting tabs so you shouldn’t be able to mix them up. You can connect the shorter plug into the passenger side ballast from the harness and the low beam plug coming from the harness can be connected to the factory low beam plug on the passenger side - the driver’s side low beam will not be connected to anything and can be tied back.

HID low beam connection

HID wiring run

HID wiring run

Make sure to connect the eyelet connector to the positive terminal of the battery before moving on.

HID wiring run

With the ballasts and harnesses mounted, you’re now ready to move on to the inital alignment and testing of the headlights!

Alignment

While it doesn’t pay to fully reassemble the headlights at this point, you will need to join the rear housing (with the mounting tabs and alignment bolts) and the inner bezel for alignment of the projectors. Set your projector/high beam housing into this housing and tighten the adjustment screws a few turns to secure them back together. If you were smarter than me, you may have followed my advice to mark the depth of the alignment bolts prior to unscrewing everything. If that’s the case, you should be able to use these markers as a guideline for where to start with your alignment.

Temporary reassembly for alignment

Temporary reassembly for alignment

Grab the D2 igniters and plug them into the ballasts on either side. Next, the bulbs can be connected to the igniters by aligning the pins on the rear of the bulbs with the slots on the igniter plugs and twisting to lock them together.

Using the original 10mm bolts we removed at the beginning, secure the housing/bezels to the frame of the car to replicate their position once everything is put back together. With the igniters connected to the ballasts, double check your wiring from earlier to make sure all of your connections are solid and switch the headlights on for the first time!

Mocking up the position of the headlights

HIDs powered on for the first time!

Pretty close to OEM leveling

You may notice the beams are not level - that’s ok! This is where we’ll use the alignment bolts and take advantage of the easy access to everything. Using an 8mm socket and ratchet or ratcheting wrench, slowly turn the three alignment bolts clockwise to adjust the aim of the beam so that the cutoff point closely matches the OEM low beam cutoff you marked on the wall way back at the beginning of the project. Be sure to use all three bolts, as putting too much strain on a single bolt can cause issues down the road.

Some troubleshooting notes: If your headlights don’t turn on, double check your wiring again and make sure the harness is connected to a solid grounding point. Also make sure all connections to the ballasts are secure - the waterproof gaskets on the plugs can make it difficult to know if they are inserted fully or not.

Once you’re happy with your alignment and have tested the function of the high beams, you can go ahead and disconnect everything from the car again and uninstall the bulbs. You may be able to get away with baking them with everything still installed, but I didn’t want to risk damaging the fragile HID bulbs.

At this point you’re ready to reassemble the headlights!

Reassembling the Headlights

Take the clear plastic lens and remove the three phillips head screws in preparation for securing the painted bezel and c-light back in. Before doing so however, take the time to thoroughly clean the inside of the lens. This will be your last chance to do so before putting everything back together semi-permanently. Also don’t be an idiot (like me) and set the outside of your lens on your dirty workbench - rest everything on soft, clean microfibers to avoid scratching the clear plastic.

Reassembly

Now carefully place the painted bezel into the lens, align the holes, and secure everything with the phillips screws you just removed.

Reassembly

Reassembly

Next, grab the Morimoto RetroRubber package and the rear housing. Wipe out/clean the housing channel (making sure to get any leftover OEM butyl) for a nice solid bond for the RetroRubber. I started at the top of the headlight, but I don’t think matters - lay a strip of RetroRubber all around making sure to not leave any gaps and that the rubber is set into the channel (I measured about 52 inches of rubber per headlight).

Retrorubber

Retrorubber laid

Retrorubber laid

With the RetroRubber in place, feed the DRL wiring through the OEM hole in the housing and gently set the lens into the housing/RetroRubber.

Feeding the DRL wiring

Now it’s time to bake the headlights again to soften the rubber before setting the lenses in place for the final seal. I did 200 degrees for 5-10 minutes, but keep an eye on the headlights to make sure they don’t get too warm.

Baking the headlights again

With the rubber softened in the oven, the last step is to join the lens and housing back together. Be warned, it’s pretty tacky so it can be hard to make adjustments. I’d recommend making sure the inside corners of the lenses are aligned and working your way to the outer corners. Double check that the clips around the edge of the lens are lined up and start applying a little pressure to join the two halves together.

Using clamps can be helpful when reassembling the headlights

I found that using a few wood clamps in strategic locations helped a ton here. Just be careful not to put too much pressure on the lenses, and be sure to set the headlight on a clean microfiber if you’re going to be working on a bench/surface.

With a little luck and some brute force, the lenses should snap back together with the housings. Double check that all of the clips are secured and that there aren’t any gaps in between the pieces. Once the headlights have cooled, it’s time to finish up the reassembly!

Headlights all reassembled!

Re-install the six phillips screws on the back side of the housing.

Since the OEM DRL bulbs are much bigger than the wiring for the Diode Dynamics c-lights, there will be a bit of a gap between the housing and the wiring itself. To prevent condensation, I used a some waterproof silicone to create a good seal around the DRL wiring.

Gap around the DRL wiring

Silicone to seal the hole

Hole sealed

In addition, the OEM high beam gaskets can be reinstalled along with the high beam bulbs.

OEM high beam gasket

For the low beams, I combined the OEM low beam gasket and the included rubber grommet from the D2S projector kit with some super glue and silicone. Be sure to give everything some time to cure before moving on (I let them sit overnight). Re-install the HID bulbs and slide the frankenstein gasket you just created over the end of the rear of the projector making sure to plug in and thread the D2S high beam wire through the hole as well.

DIY headlight gasket

DIY headlight gasket

DIY headlight gasket

DIY headlight gasket

DIY headlight gasket

Finishing Up

At this point the headlights should be ready to go back on the car for the last time! But before doing so, take a minute to clean up/tie down any loose wiring and ensure all of the connections are solid. Also make sure the DRL wiring has enough reach so that it can easily be connected to the turn signal taps when the bumper is being put back on.

Reconnecting the bumper wiring

When connecting the wires from the headlight to the harness, you may use the high beam splitter harness if you maintained your OEM high beams. Simply connect the single end to the output of the HID harness on each side and the split ends to both the OEM high beam bulb and the HID bulb high beam wiring.

NOTE: In the picture below, I simply connected the HID harness directly to the D2S high beam wiring as I was no longer using the OEM high beam.

HID high beam connection

Be sure to connect up your DRL wiring and reconnect your sidemarkers as well! If you’d like to roll without the sidemarker light, you can simply pull the OEM bulb out of the plug. I’d recommend reinstalling the plug either way to prevent moisture though.

DRL wiring connection

Once you’re ready, go ahead and follow the Preparation steps backwards to get everything reconnected. As before, I found that starting with the bottom of the bumper first seemed to be easiest.

Bumper reinstalled

Bumper reinstalled

With everything installed and reconnected, take a step back and enjoy the finished product! I took the car out for a dusk drive to dial in the headlight adjustments (there’s a great video from The Retrofit Source on the topic here) and bask in the glory of HIDs for the first time.

Closing Thoughts

What can I say besides “holy shit”? The cutoff from the D2S projectors is unbelievably sharp and the range/color of the Morimoto 5500k bulbs is just perfect in my opinion.

HID low beams

HID high beams

I couldn’t stop smiling that first drive, mostly because I knew that all of the work had been worth it. I’m really disappointed I didn’t grab more before/after pics of the OEM halogens, but rest assured the difference is clear. There’s really no comparison - the halogens were like driving with candlesticks taped to the front of the car compared to the HIDs.

Aligning the HIDs

OEM output

Not only is the new HID setup more badass in every way, but it has a real effect on how safe I feel driving at night now. Before I felt like driving with my low beams on was asking for a deer to jump out at me, but no longer. I have much more confidence on dark backroads and actually look forward to driving after dark! I plan to pick up a set of LED fogs as well, which should help supplement the far edges of the HID beam pattern and really fill out the rest of the front end.

HID low beams while driving

In addition, the Diode Dynamics c-lights have a brilliant, crisp white output and have totally transformed the front end. It’s got an infinitely more refined look and really makes the car stand out in traffic. I find myself following black cars just to see the reflection of the c-lights in their bumpers now!

Diode Dynamics c-lights

Diode Dynamics c-lights

Diode Dynamics c-lights

Diode Dynamics c-lights

Diode Dynamics c-lights in amber mode

Overall I would give this project an 8/10 in difficult, but 10/10 in value. The Subispeed LED headlights are an attractive option, but at over $1000 for a set, they can be a tough pill to swallow. For less than $500, the Morimoto D2S retrofit is one of the best mods you can do for your WRX.

If you are looking into doing a retrofit yourself, please don’t hesistate to shoot me an email or leave a comment down below if you have any questions! Thanks for stopping by!

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