When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hi everyone, looking for any advice on trying to swap a factory set of HID lights from a gd3 to a gd1 I picked up a set of factory hid lights from a jdm 2007 gd3 yesterday and I'm looking to retrofit them to my 2003 gd1 with factory h4 headlights , can't find any information on this at all so no idea if anyone's tried it or ever succeeded with it, but I'm interested to see if it could work as expected. All of the connections are the same apart from the H4 light. Obviously having a regular H4 connection and the other lights having only the connection for the ballast I'm not sure if I require an adapter/ need to cut and join wires or if this is even possible at all with other other parts to support it. If anybody has any information on the topic please let me know cuz this is out of my area of knowledge
Thanks Hid's left ,h4s right Hid light connections
[img alt="Ballast connection
"]https://cimg0.ibsrv.net/gimg/www.fitfreak.net-vbulletin/1500x2000/pxl_20260510_180935334_43bcd4f6318ede5c2a18a7b09cc 93bc5df52e8ab.jpg[/img] Ballast connection Original h4 light connections
HIDs are plasma arc (a stable "spark" in special gas) lamps, rather than tungsten filament (thin glowing-hot wire). They require very high voltage to start (strike the arc) and a circuit to keep the arc stable at the desired power level - that's what the ballast handles. The wiring between the ballast and bulb usually has thick insulation, designed for very high voltages, similar to spark plug wires (not that Fits ever had those). I don't see any such wiring in the pics, so I assume the ballast is in the housing or maybe in the housing cap.
I'm not sure what you purchased but they're not HID projector headlights.
It's possible that someone just put HID bulbs in regular halogen reflector headlights. If so, you could have done that with your existing headlights. Either way, you don't want to do that because it scatters lights which means less light for you and more blinding light for oncoming traffic.
Sorry to say, but it appears you wasted some money.
Correct. The important detail is whether the reflectors were designed for HID bulbs or not. HID reflector headlights are very much a thing, though they're usually accompanied by a separate high beam reflector and bulb.
HID reflector headlights are very much a thing, though they're usually accompanied by a separate high beam reflector and bulb.
Wait, seriously? I know I don't know everything (I know very little actually) but I've never seen or heard of HID reflector housings. That's interesting. This would be a first for me!
If that's the case, sorry for my aggressive responses in the beginning lol.
I'm also skeptical - if the big reflector is the HID low beam, where's the high beam? I've seen plenty of bi-HID projector headlights (projector with movable cut-off shutter), but never heard of bi-HID reflectors.
I want to see that conveniently-missing ballast connections pic, and a pic of the headlight with the lens polished clear.
I'll send a picture when I get home from work they're d2r philips bulbs not the roadmanners projectors, I did originally consider those but they're only for lhd models and I'm in Ireland where we drive on the right
I'll send a picture when I get home from work they're d2r philips bulbs not the roadmanners projectors, I did originally consider those but they're only for lhd models and I'm in Ireland where we drive on the right
Sweet! I'm sorta afraid I'm gonna look like a fool but I'm still super interested in finding out!
In all seriousness, Eddie's headlights (original and fancy versions) have power height adjusters on them. Second pic, left side: the 3-wire device with the orange nub is the adjuster servo. Also seen on the last pic (existing headlight) with a white cone to guide a screwdriver tip for manual adjustment. The driver has a switch (usually a multi-position knob or slider) on the dash that commands the headlight aim up and down. The driver adjusts it based on vehicle cargo load and driving conditions - Americans are too dumb to be trusted with such a device, so you only see them associated with auto-leveling headlight systems.
You can get LED Lights that fit into the stock light housing.
Just like fitting the original Halogen Lights.
No adjustments of the Lights.
No extra wiring.
Unless you have the correct housings for it, LEDs won't work. LEDs simply cannot match the same light distribution as a halogen bulb so they'll produce hotspots if installed in headlight housings designed for halogen bulbs. They might look brighter, but the light won't be properly focused. Think of it like when you compare a spot light to a flood light. Headlights should be more like a spotlight, focusing the lighting forward toward the road, and away from oncoming traffic. LEDs in a halogen housing will be more like a floodlight, throwing light all over the place in front of you, but not focusing it down-road where it needs to be. Oncoming traffic will be blinded by the scattered and unfocused light, and you, the driver, will have less usable light because it's being thrown in all different directions rather than where it needs to be.
Every company will tell you that their LED bulbs are a perfect match or that their LED bulbs will work in place of halogen bulbs. That's marketing. That's a lie.
Everyone that puts LED bulbs in their halogen housing will tell you that no one flashes them so LED bulbs are just fine. That's confirmation bias. That's a lie.
You should not put LED bulbs in headlights designed for halogen bulbs.
Originally Posted by bobski
In all seriousness, Eddie's headlights (original and fancy versions) have power height adjusters on them. Second pic, left side: the 3-wire device with the orange nub is the adjuster servo. Also seen on the last pic (existing headlight) with a white cone to guide a screwdriver tip for manual adjustment. The driver has a switch (usually a multi-position knob or slider) on the dash that commands the headlight aim up and down. The driver adjusts it based on vehicle cargo load and driving conditions - Americans are too dumb to be trusted with such a device, so you only see them associated with auto-leveling headlight systems.
I knew nothing about this. Holy cow I wish I had manual adjusters on my headlights :<
Kinda reminds me about so many dummy gauges vehicles have because drivers are too stupid to understand how they work and freak out when the gauges move as intended. "Oh my god, why is my oil pressure gauge moving?!"
Last edited by Detergentcandy; May 13, 2026 at 06:24 PM.
Reason: I suck at grammar I guess.
Every company will tell you that their LED bulbs are a perfect match or that their LED bulbs will work in place of halogen bulbs. That's marketing. That's a lie.
Everyone that puts LED bulbs in their halogen housing will tell you that no one flashes them so LED bulbs are just fine. That's bias That's a lie.
You're describing the worst-case scenario, and going off the deep-end with it. There are applications where LED retrofits work well. There are applications where LED retrofits do not work well. Rather than try to map out every headlight design, most vehicle regulatory organizations just ban LEDs in halogen fixtures. That resulted in a wild-west of outlaw "for off-road use only" products. Some come very close to the size, shape, placement, and intensity of halogen filaments. Such retrofits work well for most headlight fixtures (though there are outliers). The outlaw status means there's also LED retrofits with the wrong size, shape, placement and/or intensity. They can be problematic in all the ways you listed.
TBH, your worst-case scenario is more common when HID bulbs have been retrofitted into a halogen fixture. Without some major modifications to the bulb design, it's impossible to make the HID arc follow the same shape, and have the same contrast lines as a halogen filament. The HID arc has the wrong shape and intensity, even if you get its size and placement right. Projectors seem to be the only applications where HID retrofits can produce a proper beam pattern.
You're describing the worst-case scenario, and going off the deep-end with it.
You're not wrong.... but to be fair, I'd hold my statement true for the "majority" of LED bulbs being installed. Since I imagine most of them are coming from some no-name vendor on Amazon or Ali Express with little to no actual engineering put into them.
I'll agree that while some LED bulbs can get close-enough to halogens where the reflectors can aim the light decently, those are the ones that most people are not installing as often due to the cost since actual engineering went in to designing them.
I'll try being a little less hard-lined on some of my opinions :P
But boy howdy, I am SO TIRED of bad car modifications and poor choices.
Holy cow I wish I had manual adjusters on my headlights
You do have "manual" adjusters. Second Eddie pic: consider the bulb housing cap as a clock. See that toothed wheel at the 11 o'clock position? That's a manual adjuster. In this case, it sets the "zero" position for the power height adjuster. The silver circle at the 2 o'clock position is the left/right manual adjuster. You have a similar pair of manual adjusters on the back of each of your headlights. They're usually designed to be turned with a no. 2 cross-head (such as Phillips) screw driver, such that the arms of the screwdriver's cross "walk" their way from one wheel tooth to the next as you turn the driver.
edt: Here's a pic from the GE service manual:
... And the adjustment instructions:
Originally Posted by Detergentcandy
You're not wrong.... but to be fair, I'd hold my statement true for the "majority" of LED bulbs being installed. Since I imagine most of them are coming from some no-name vendor on Amazon or Ali Express with little to no actual engineering put into them.
That was the case early on - maybe 15 years ago before LED manufacturers had devised LED emitters compact enough to mimic halogen filaments (it was a cooling issue). For once, market forces actually prevailed in driving the creation of LED "bulbs" that work well. If it has tiny rectangular LED emitters, it's probably okay from a beam-pattern stand point. That said, they're nearly all over-powered. Something in the 10-15 watt range (per bulb, low and high beams addressed individually) should get you legal levels of light output.
Originally Posted by Detergentcandy
But boy howdy, I am SO TIRED of bad car modifications and poor choices.
That's fair. But it's also what you get when a country's richest individuals are allowed to spend their money on stupidifying the public in an effort to more easily exploit them. Welcome to the dumpster fire.
