HID Lights Update on the Diode Modification

Discussion in 'Technical' started by phutumsch, Oct 17, 2011.

  1. phutumsch

    phutumsch Its 'Foot-hum-sshh' !!

    Having read many threads both in Aus and in the UK about the main beam staying on when you flash, with regard to the pin 5 needing to be earthed from the headlight relay (in the large box passenger side, relay is the one nearest the front of the car).

    It's the fat green wire that requires grounding on the body

    If you just snip away the black tape from the large bunch of wires at the corner of the box, you will be able to just tease this green wire up to enable you to splice into it and ground a wire from it.

    I always had an issue with the hid lights being flashed during the daytime after carrying out the above and coming on with the main beam, I have now done the diode mod on my Z and it now works perfectly, just how I want it to :yes:

    The original modification stated to use a Nissan relay with numbered pins 1,2,3 and 5, I have done it with a normal more common relay and the following tells you which pins go with which wire and where they go to.

    Basically what I am now going to describe is pretty much the same but a touch simpler I hope with fresh pictures to show, especially the work needed in the light pod.

    #1, From your new relay position marked 30 connect the wire that you have after splicing into the fat green wire that comes from pin 5 in the passenger side fuse box. This is the quick modification described above and what I carried out initially. Yellow coloured spade in the pic below.

    #2, You now need a wire from the positive side of your battery to pin numbered 85 on your new relay, put an inline fuse in this feed with a 1 or 2 amp fuse. Red coloured spade in the pic below.

    #3, Now your new relay needs a grounding/earthing wire to position 87. See the point I have used in the picture. Black coloured spade in the pic below.

    #4, You now need a longer wire that needs to go from position 86 of the new relay to the light pod. Blue coloured spade in the pic below.

    [​IMG]

    Now at the light pod, you do gain more access to the wires if you remove the pod back, sever the 2nd pink one in wire about 3 inch from the connector itself, on the pink wire connect your new wire from your new relay position 86 and also the leg of the diode needs to go on here, you must get the diode the correct way round so please note the pic where the band on the diode is nearest the connector. Now on the other diode leg connect it back up with the other side of the pink wire.

    [​IMG]

    Ebay is a good source for the inline fuse and a relay, just search with '1N4002' for the correct rectifier diode.

    Mine is all rough to show so of course tidy your wires and relay neatly and use crimps or solder them together in the light pod.

    To summarise what now happens and this must be everybody's goal who has HID lights fitted in their dipped beam.

    When hid/dipped lights are off in the daytime and you flash just the main beam will come on and the hid/dipped lights will NOT.

    When the hid/dipped lights are on at nightime and you go to main beam or flash, main beam will come on and the hid/dipped lights will stay on, be unaffected with no interuption to their supply.

    Having done this and posted on the UK site, I thought I would share it on here, hope I have helped,
    Andy.
     
  2. Altari

    Altari '89 2+2 TT Manual

    Exactly what I was looking for. Thank you!
     
  3. phutumsch

    phutumsch Its 'Foot-hum-sshh' !!

    You are very welcome sir.

    Allow me to clarify further, a common misconception with this modification.

    You can use a short length of wire on the drivers headlight to tap into the neutral and earth it to the body and job done, this will take you 10 mins.

    This 10mins mod and the earthing of the fat green wire of pin 5 of the relay work exactly the same.

    When our cars left the factory and before HID lights existed, with dipped on and you flash or go to main beam the dipped lights go out for as long as you are pulling back the stalk, then they revert back again, both these quick mods all they do is stop this from happening.

    The diode mod will do that also, but it's selling point is that it stops the hid lights from coming on when you flash in the daytime, ie when your hid lights are in the off position
    __________________
     
  4. Chrispy

    Chrispy Pretentious Upstart

    This is similar to a old writeup I used years ago which was translated from Japanese. There was no additional wiring besides installing the diode in the left hand pod in the cabin.
     
  5. phutumsch

    phutumsch Its 'Foot-hum-sshh' !!

    I pm'd you in April 2010 with regard to posts I had seen of yours and about where this diode goes but you informed me you had sold that particular car so could not just look.

    I mention the original modification in my post and having seen this, I can confirm it did involve the 4 wires and a Nissan relay was used, I have found out using a common 4 pin relay which wires go where and to which numbered pins so thought I would share and use some new pics ;)
     
  6. phutumsch

    phutumsch Its 'Foot-hum-sshh' !!

    These instructions do work as I followed them practically to the letter when I did the mod on a friends car and I took a video to show what it actually does, please note wires were tidied after the vid was taken.
    Some notes though that may help you further :
    #1 does work above but it's easier if you splice in a wire onto your negative spaded wire of the HID kit and send this to position 30 on the relay. This is the quick modification that advises that this wire is grounded but for this diode relay mod it goes to 30 on your new relay.
    You can use a 5 pin relay, you just ignore/do not use position 87a.
    We used a nice big fat 10 amp diode in the light pod, you may notice that a black and black/red 2 core wire connects here, one of these two goes through the bulkhead and to position 86 as stated above and one was left as a spare should something be needed pod to engine bay in the future.
    Finally, I do not think it matters which of the two pink wires you connect the diode to at the pod as one is L/H and the other R/H and as long as one side is done it'll work.

    http://youtu.be/NRWO8u1T4Pw
     

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