Wireing bi-xenon bulbs to work when flashing

Discussion in 'The Projects Forum' started by Davidstrawhorn, May 9, 2016.

  1. Davidstrawhorn

    Thread Starter New Member

    May 9, 2016
    Hi folks,
    Joined the forum to ask some advice on a project I'm working on.

    I have fitted bi-xenon projectors in my car that used to use a two bulb set up for the high/low beams. The low main beam halogen bulb has been replaced by an HID bulb and comes on with the usual switch and the high beam bulb has been removed and replaced with the bi-xenon shield solenoid. My high beam works great but only when the low beam is on - meaning I can't flash my lights during the day when the low beam is off (the solenoid still functions but there is no light from the HID as this is now the only bulb and only functions with the low beam switch).

    On cars that are factory fitted with bi-xenons, when they flash their high beam during the day or with their lights off, the HID ignites to flash and the solenoid activates the shield.

    I have connected the positive end of the solenoid to the low beam circuit (Fig 1.0) so when I flash the the high beams the hid bulb ignites and the solenoid activates. However when I turn the low beams on, the solenoid activates essentially turning it into another high beam switch. I have played around with the idea of putting a diode in as seen in Fig 2.0. Would this work?

    While writing this post out I came up with the idea of connecting the circuit after the solenoid as seen in Fig 3. Would this achieve what I'm after or would the flow simply bypass the HID bulb and take the path of least resistance? Please tell me I've not stumbled across a completely obvious and extremely easy solution that's been staring me in the face all along?

    Many thanks for taking the time to read my post and special thanks to those that take the time to help me on this!
    Kind regards,
    Screenshot_20160510-000232.png Screenshot_20160510-000326.png Screenshot_20160510-001209.png
  2. TheButtonThief

    Active Member

    Feb 26, 2011
    Personally, I think HID's on the full beam circuit is stupid. When driving with you're full beams, you're constantly turning them on and off when driving at night and during they're used as a light horn. Unlike a regular lamp with a filament, an HID's longevity is determined by the number of on-off cycles rather than operational hours so it's a bad idea to use them on a circuit that you know is going to get switched intermittently.

    Besides, even if the number of on-off cycles wasn't an issue, they still take time to "warm up" once turned on so they're useless as a light horn and with respect to driving with full beams at night, you may need to turn them off for a passing car before they've even reached full brightness.
  3. Davidstrawhorn

    Thread Starter New Member

    May 9, 2016
    They're not useless as a light horn. When an HID ignites it sort of "peaks" then dulls until it warms up (<3seconds). The hid bulb isn't constantly being turned on/off at night with the cycle of your high beam. A bixenon setup uses one bulb and a shield to cutoff the light output. When you flick your high beam switch, the solenoid pulls the shield down allowing the full beam pattern to display.