They will fit and should work. You'd have to mount and wire the ballasts in however. I'm not sure if there are any easy connectors out there to do so. Also, the STI headlights are motorized for leveling, so you have to take that into account as well. I thought WRXs may have been prewired for that, but you'd still have to find a switch.

 

Hey thanks for the reply Mikie, So I'm gonna be honest with you, this is all new to me. I've been doing some research on all this and I'm seeing the word 'rewiring' being thrown around which scares me. I'm currently in contact with the seller of the '05 STi HID Headlight assemblies and here's what he said they came with.

"Headlights will come with 2 pairs of HID Low beam bulbs, OEM Color temp D2S Bulbs and Aftermarket 10K D2S Bulbs. Both pairs work great! In the pics are the 10K's, however I reinstalled the OEM's when I removed the headlight housings. Swap them out with the 10k's if you want it like the pics (More blue). These will fit all 2004-2005 Subaru Impreza WRX and STI models.

Please note: Wire Harness's and sockets for turn signals, side marker lights, etc.. will not be included with the sale, simply plug and play with your existing wires and bulbs. for a perfect OEM install. I am including the high beam bulbs pre installed, as well as a free pair of white LED 194/168 bulbs for your running lights! If your car did not originally come with OEM HID, minor re-wiring may be necessary to instll these headlights but is totally possible as I know many people who have done this upgrade! I will also include a FREE Relay harness that you can modify for installing HID's into a non HID Vehicle if your car came with halogens from the factory."

So can you explain to me what he means in his last few sentences about relay harnesses and HID vs non HID vehicles. My '04 WRX is obviously a non HID vehicle so I'm assuming that relay harness will come in use right? Also did my car come with halogens from the factory?

Sorry for my confusion on this, I truly appreciate your help!

EDIT: I also found out that he has an '05 STi, not an '04 so does that change anything?

 

HIDs require more power or different power than typical halogens, which is why you'd need some kind of rewiring as they are explaining.

I had an 05 STI which had the HIDs obviously, but I never looked too far into it because I simply knew what it was. Sounds like it needs a connector/relay to make wires line up, similar to how a Radio wire harness works. It will put wires where they need to go.

 

Will I need to purchase anything extra to make these work?? You said something about them being motorized, are they supposed to be operated from inside the cabin or on the headlight assemblies themselves. The seller does claim that he is including a relay harness. Another question I have, will I need to purchase the ballasts or will they come with/apart of the headlight assembly.

The seller said he's not including "Wire Harness's and sockets for turn signals, side marker lights, etc.."

I appreciate your help so far Mikie13, I'm also doing my research on both here and NASIOC but I'm not having too much luck on finding definitive answers or tutorials :/

 

That's honestly beyond me. I was mostly speculating and adding some logical thoughts about it based on average knowledge.

The lights should work outside of the motor leveling switch, as long as they are already set at the height you want. But yeah, the headlights were controlled from inside to three different height levels via a switch. I think you can get by without that part of it though.

 

Couple threads I found with a quick Google search:

sti headlights into 04 wrx - NASIOC

Installing STI headlights on WRX (04') - NASIOC

 

Yeah I actually had the top one book marked for when I get them lol

Here's what the seller is telling me,

"Hello, Well its actually a lot simpler than you probably think. On your headlights, after you remove them, you need to unscrew the 2 metal mounting studs out on the outer edge of each side and screw them into the new headlights I sent you. Now they are ready to mount. As far as the light and harness connections... Too simple. The running light, turn signal and high beam will be a direct plug and play. Just plug the wire connectors and insert the bulb holders where they are supposed to go and your golden. The only connection you have to slightly modify is the low beam (HID). very simple too... On the OEM HID headlights There are only 2 wires going into the ballast/igniter. All you have to do is take the two wires that originally powered your non-hid low beams, cut off the plug and splice them into the 2 ballast/igniter wires on the bottom of your new OEM HID headlights. Don't remember the colors off the top of my head for the non-hid OEM low beam plug, but they are like LED's and are polarity specific. So if they don't work one way, simply reverse the two wires and they will work. I included an aftermarket relay harness I had laying around the shop if you choose to use it or not, it is up to you. It will be a little more wiring, but will give your new HID's more power since your car did not come with them from the factory. If you use it, you are going to have to cut the plugs off and hard wire the relay harness into your existing wiring. Like I said, it's not required for your headlights to work... but is an option for you if you need peace of mind that they are getting enough power to run. You can easily find info online how to wire a relay harness for headlights/HID."

Anyways, When I get the headlights and attempt the install, I'll post my experiences to help others who may be having some troubles with this headlight swap.

 

Ahhh I see what he's saying.

I think if you go back to the first link that I posted (that you book mark), they talk about a relay/harness from Lightwerkz. If you were to get that, I imagine that you wouldn't have to do any cutting/splicing!

 

Yeah I think I'm just going to go with the product from Lightwerkz OEM STi HID Wiring Harness

It seems like a more reliable and simple way in doing this, I'll dish out the $75 for it. Also the customer service there is extremely nice and answering all of my Q's about their product.

I'll post back with pics of the installation!

Thanks again Mikie!

 

Alright so I finally got around to installing the '05 STi Headlight Assemblies on my '04 WRX.

I honestly couldn't have asked for an easier install!

For anyone who is going to do this install, I would recommend this OEM STi HID Wiring Harness This is so you won't have to do any splicing or worry about any fuses. It's literally plug and play & the customer support is great if you have any questions!

Here's a picture of the before and after of my headlights, the top headlights are my original WRX headlights and the bottom ones are the new STi headlights. They were a direct swap. Also if you look, the right driver's side may seem to have a small gap along the bottom of the headlight, it's because my front bumper is sagging, previous owner must have hit something. That'll be my next project, Just need to get some zip ties

 

Glad it all worked out for you man!

 

Nice! They look good.