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LED/projector headlight upgrade

Discussion in 'XJ Modifications' started by josh the man, Jan 14, 2021.

  1. josh the man

    josh the man New Member

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    Hello all,
    Sooooo I installed an LED/Projector headlight. Works fine, but it has that typically flicker at idle. I was wondering if I could bypass the alternator by connecting directly to the battery with a relay and fuse. I bought a car kit that piggybacks off of the original plug so that you still get the functionality of your switches and also the function of only turning on when the engine starts running, but it gets the source from the battery which should eliminate flicker. I haven't set it up yet as the harness will need to be modified for just one light rather than two. Has this been done? or is it going to somehow mess up the wire system?

    PS update photo of my JX550 maxim!

    Attached Files:

  2. Fuller56

    Fuller56 Active Member

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    Cary, NC (winter) Harpursville, NY (summer)
    Yes, you can do that. I have done it on several bikes. I use 2 relays, 1 for high beam, 1 for low beam. Run the fused power from the battery to feed the relays. Trigger the relays from your original headlight plug so the normal switching works. Remember to increase the size of the wires from the relays to the lamps and a good heavy ground wire to the battery. With LEDs your probably don"t need the heavier gauge wire.
    josh the man likes this.
  3. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    At My Computer
    We have a nice, heavy-duty headlight relay harness that should solve your problem, and it's plug-and-play:


    Headlight Relay Wire Harnesses:

    In order to take full advantage of either stock or aftermarket headlights, full battery voltage must be available at the headlight terminals. The long run of under-sized factory wiring, and the stock headlight toggle switch, will not allow your headlight to receive a full dose of current, and thus your headlight---the most critical safety component on your bike----will be suffocated for amperage and will far less brighter than it should be. The solution is a professionally assembled, plug-and-play RELAY-CONTROLLED HEADLIGHT HARNESS that uses your headlight switch to actuate an electrical switch (the relay), which then allows full battery power to your headlight.....allowing it to shine like the sun!

    REMEMBER, as per the discussion previously, that headlights are rated at 12.8 volts, but typically receive a lot less......and that's the main reason why your headlight is so dim.

    These headlight relay wire harnesses are simple to install-----even for the most electrically-challenged mechanics-----and come with extra terminals, cable ties, illustrated instructions, and do not require cutting your original wiring harness at all. Your stock headlight switch now powers the relays, rather than the headlight, and thus no new switch is needed. Installation time varies, but normally requires 30 minutes or less to install (mostly involving the removal and replacement of your seat and gas tank, and the routing of the wire harness), and absolutely no soldering is required.

    NOTE: when installing a headlight relay harness on any model which utilizes a "computer display" gauge package (XJ750 Seca, XJ750 Euro, 1982 XJ750 Maxim, and XJ650 Turbo models) which have a headlight "testing" circuit built into it will experience a HEAD warning on the LCD display screen, and the flashing red WARNING light will blink every time the bike is started! There is no way to overcome this issue when using a headlight relay harness on these models. Depressing the right-side rectangular WARNING CONTROL button TWICE on the gauge cluster will eliminate the red flashing warning light for the headlight issue, but this must be done every time the bike is started. The HEAD display on the LCD screen will remain illuminated, and cannot be eliminated.

    HCP14749 Aftermarket headlight RELAY-CONTROLLED HEADLIGHT HARNESS, with plastic headlight socket.

    HCP14750 Aftermarket headlight RELAY-CONTROLLED HEADLIGHT HARNESS, with hi-temp, hi-performance ceramic headlight socket.
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  4. Yammaat

    Yammaat Active Member

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    I haven't had any problems with the LED headlights. Just plugged it in and presto.. no flickering whatsoever.
    On the dash the headlight warninglight stays on.
    I read somewhere that this is to eliminate by tweaking the computer with a resistor but I don't care about the dashnotificationlight staying on.

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