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Thread: E46 Halogen -> OEM Xenon -> aftermarket projector retrofit questions

  1. #1
    Join Date
    Mar 2019
    Saratoga, CA
    My Cars
    2002 BMW 325xi

    E46 Halogen -> OEM Xenon -> aftermarket projector retrofit questions

    Many of these topics have been covered in earlier posts in this and other forums, but after doing research I still have some questions relating to my specific project. Thanks in advance for reviewing my questions. Hopefully, this will be useful to others as well.

    For some background, I have a 2002 BMW e46 sedan (325xi) that has factory halogen headlights. The light output is dismal, so an upgrade has always been planned. Because I wanted flexibility on bulb selection, I purchased a pair of used OEM ZKW bi-xenon headlights off of eBay to upgrade with aftermarket projectors. They were purchased from separate eBay vendors and therefore cars, but both use an OEM Mitsubishi ballast. I have no idea yet whether the ballasts work but will likely use 35W OEM replacements if they don’t. Purchasing used headlights also allows me to take my time with the hardware retrofit while the original halogens are in place and keep the car on the road. I do not have DRLs coded for the car but am considering this along with the bi-xenon upgrade as a way to continue getting utility from the high beam lights.

    A couple more points and goals:

    • Though I want to safe and reliable lighting system, I am interesting in minimizing extra hardware and harnesses in the engine bay. I would like avoid relays, capacitors, etc as much as possible.
    • My hope is to use a Y-adapter from a projector retrofit company to energize the bi-xenon shutter solenoid from the halogen high-beams. This would avoid the necessity of running a wire from the LCM to control the shutter.
    • According to at least one retrofit kit vendor, the high-beam halogen voltage in DRL mode will not damage the solenoid in the bi-xenon aftermarket projectors, assuming a Y-adapter is being used. Assuming no relays are used, this implies that high beams will be generated by BOTH the bi-xenons AND the high-beam halogens, which I am OK with. I don’t see a power/fusing issue because I believe that my current OEM halogen setup keeps both low and high ON when the stalk is pushed forward.
    • I have never attempted reprogramming modules but am willing to learn. TerraPhantm has posted on this many times in the past which I appreciate. However, I want to minimize the necessary coding for my specific application to avoid the risk of “bricking” my car, if that is even a valid concern. I have what I think is called a “low” instrument cluster, so headlight warnings may not be an issue, though I am not sure about this. If I want DRLs then I assume that I will at least need to code for this function.
    • By keeping with OEM ballasts, I hope to avoid CANBUS errors and increase odds of compatibility.
    • I am not interested auto-leveling or large BMW harness retrofit projects.


    1. I have seen posts from others who have retrofitted OEM xenons into halogen cars without any coding whatsoever while not using relays. Some report no issues while others report flickering. Why does recoding the car for xenons evidently eliminate flickering? What is the specific electrical reason for this? I would not think that halogens would use either a lower voltage or pulse width modulation to control power.
    2. If I only need to program DRLs and can get by without LCM coding, will the PA Soft /BMW Scanner programmer be a safer and sufficient method for coding as opposed to NCS Expert? Is “Mike’s tools package download” the best tools platform to date?
    3. If I want to have/preserve halogen high-beam, DRL and flash-to-pass, should any LCM recoding choose “xenon” or “bi-xenon”? Given that the xenon option changed in 2002 with the factory bi-xenon evidently disabling high-beam halogen function, should I choose “bi-xenon” then enable halogen high-beams, or “xenon” to preserve halogen high-beams? Does it matter?
    4. I have seen mention of issues with cold and/or warm bulb checks. Why, and what coding changes should be made to address this?
    5. Is there any other reason for using power relays in a BMW xenon retrofit, other than avoiding LCM recoding? The battery is in the trunk, so I don’t see an advantage with reducing voltage drop. Maybe the odds of flickering are reduced by avoiding the factory harness power delivery and related to my first question.

  2. #2
    Join Date
    Sep 2005
    Salem, MA
    My Cars
    03 zhp, 97 e36m3, 04 zhp
    1. Depends on the quality of ballasts more so than coding. If you go with OEM ones that were built into the housing, you will have cleaner appearance and less of a chance for flickering.
    2. PA Soft is ok to use.
    3. Xenon option. Bixenon will energize shutter solenoid allowing them to stay open as you push the stalk away for high beam (without utilizing halogen high beam).
    4. That's why you code for xenon lights. I believe it uses different voltage to "look" for bulb out
    5. Relays are there to protect wiring. Wiring loom gauge haven't changed between halogen and Xenon setups, so I don't see the need for relays in the car that was designed to run these in the first place. In older pre-xenon cars, use of relays is more relevant.

    Matsushita ballasts are good, but if your housings were shipped to you with ZKW (whoever makes them for ZKW- probably Hella) just use those for cleaner integration.
    Last edited by Mless5; 03-12-2019 at 03:46 PM.

  3. #3
    Join Date
    Mar 2019
    Saratoga, CA
    My Cars
    2002 BMW 325xi
    Thanks for the info. It sounds like I am on the right track. Based on some other posts, I believe that the only settings I need to worry about in PA Soft are a) setting Daytime Running Lights, and b) setting "xenon with AHL"

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