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Can Halogen Headlamp Assy be Retrofitted with HID?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jimolson, Dec 3, 2018.

  1. jimolson

    jimolson Member

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    I have a 2009 Pri equipped with HID headlights. I like them and would like to continue using HID headlights. They are generally brighter than halogen headlights.

    However, my HID headlight fronts are severely fogged after 180k miles of driving. I'm not fond of the 3M headlight polishing kits because no one has devised a post-polishing UV sealant that keeps the repolished headlights clear. They fog again very quickly after polishing because the factory UV coating was polished away.

    I can find on EBay tons of low-priced, all-new replacement headlight assemblies but they are for the halogen versions, not HID.

    I've guessed that Toyota's headlight vendor was probably sharing plastic parts between his HID and halogen assemblies. If true, and if it applies to the aftermarket vendor's housings, it might permit me to transfer non-plastic parts from my fogged HID headlights to new halogen headlight assemblies.

    Does anyone know if this is possible?

    Aftermarket headlight makers like Eagle Eyes always ship their assemblies fully loaded and ready to use. If their **plastic subassemblies** are compatible with both HID and halogen headlights, they would not advertise them as such.
     
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Man, what a minefield... just to start unpacking....

    Halogen headlight buckets are meant for halogen bulbs. The optics are calibrated for that filament, and there is no glare shield needed because halogen sources aren't bright enough to require one.

    HID buckets are different. HID burners have very different mount bases from halogen bulbs, for several reasons. One of them is to prevent the use of HID burners from being used in halogen buckets. Needless to say, this has not stopped the outlaw cottage industry of disassembling new HID burners and reassembling them onto bases meant for halogen bulbs to create something that was never supposed to exist.

    HID buckets are set up to work with automatic beam leveling systems, which are legally required for HID usage. It's not clear to me whether the halogen bucket would work the same way. Sometimes the leveler system is built into the bucket, sometimes it is a separate part.

    Be careful mixing and matching, you could wind up in a weird situation with aftermarket buckets where you require the handmade HIDs with halogen bases, only to have the car disable the headlight because it isn't getting a self-test signal back from a leveler assembly that is no longer present.

    I use ordinary clear coat paint after polishing headlight lenses. Adds ~24 months to the effect.
     
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  3. VFerdman

    VFerdman Senior Member

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    Short answer: YES!

    Longer answer.
    The lenses are attached to the rest of the headlight assembly using similar glue that holds your windshield on. If you place the headlight assembly into an oven preheated to 200 degrees F for about 7 minutes, the glue will soften and you'll be able to remove the lens. If lenses on the aftermarket assemblies are the same shape as your stock HID ones, you can remove the hazy originals from the stock buckets, remove the clear lenses from the aftermarket (halogen) buckets and swap them out. You can buy the new glue strips in an auto parts store or just re-use the old stuff by loosely re-assembling the lens and the bucket and placing the 200 degree oven for 7 minutes, then pressing everything back together while it cools. Attached are pictures of my halogen assemblies opened up in order to retrofit HID projectors into them. Your project is a bit different, but the lens removal tips my prove to be useful.

    If all else fails, you can purchase an HID projector kit for $150 from "TheRetrofitSource" and do what I did to the aftermarket halogen assemblies.

    Also, I saw a YT video about buffing the lenses out and covering them with something that somewhat replaces the original clear coat and protects the lenses after they've been buffed. I have not personally tried buffing out lenses (my '07 was lucky to keep clear so far).

     
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  4. VFerdman

    VFerdman Senior Member

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    Halogen assemblies DO have a glare shield, but it's very different than HID. I had to remove the glare shield on my halogen assemblies to retrofit the projectors. It's not a big thing, but it prevents the halogen bulb from shining up and forward. The high beam turns on a second filament that is located so as to bypass the shield and shines up into the reflector. Forward is blocked by a cup-shaped piece of steel.
     
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  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Fair enough, yes they do use glare shields in some halogens. But it's not at all like in (some) HIDs where the glare shield actually moves to change the beam from low to high.

    Overall I like the idea of a lens-only-swap. I would expect the rest of the native toyota HID bucket to be higher quality than anything aftermarket.

    Plus, when you've got a car with actual legal HIDs it seems awful to hack it up with outlaw parts.
     
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  6. VFerdman

    VFerdman Senior Member

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    I agree, but the HID Gen 2 lights are not projectors and therefore may not be super-friendly to head-on traffic. They are DOT compliant, though and you can't shake a stick at that. I love my projector conversion (compared to the stock halogens), but it lacks leveling and I am not sure how that affects anything as I have had a full car (4 adults and one kid in a car seat) at night on two way roads and no complaints from oncoming traffic, nor did I see the cutoff line wander up into the tree tops. If I had stock HID, I'd try to keep them, though.
     
  7. jimolson

    jimolson Member

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    Thanks to all for your thoughtful posts on this topic. It appears that the answer to my original question is, practically speaking, no.

    Based on that, has anyone seen after-market HID headlight assemblies for Gen II Prii, with or without transferring metallic hardware to the new "buckets"?

    I suspect the shortage of sellers of replacement HID assemblies is associated with the industry-wide expectation by body shops that replacement headlights arrive ready to install.

    And that expectation probably stems from the fact that there are minor hardware differences between the original Toyota-made headlights that would make transferring their metallic parts difficult.