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The A3/S3 LED Bulb "how to" Guide!

Discussion in 'A3/S3/Sportback (8P Chassis)' started by tobycruse, Nov 21, 2008.

  1. tobycruse
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    tobycruse Member

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    [Nov 21, 2008]
    Audi A3/S3 LED Project

    At last here is the “how to” guide for installing LED’s for the interior and exterior bulbs in an Audi A3/S3.

    You will need:-
    • 5 x 2W 150 Ohm resistors - www.maplins.co.uk – product code: D150R (150 Ohm is the maximum resistance you can use, this has been tested and proved. Any higher and the computer will not be fooled into thinking there is a bulb there)
    • 1 x Soldering iron
    • Solder
    • 4 x BA9S T4W Flank LED bulb (eBay) – Map reading lights
    • 2 x 42mm LED festoon bulb (eBay) – Front ceiling lights
    • 2 x 36mm LED festoon bulb (eBay) – Number plate lights - Use metal LED's NOT plastic. See important note at bottom of page!
    • 5 (for 3 door) or 7 (for 5 door) x 168 194 refractor wedge LED bulbs (eBay) – Puddle lights, foot well and boot

    IMPORTANT NOTE: I discovered when ordering bulbs off eBay that they are not all the same colour white. The difference is only very slight but if your ceiling festoon and map reading bulbs are ever so slightly different colour white, would it bother you? It bothered me! The only way I got round this was trial and error. I ordered several different types of festoon bulbs off eBay to match my map reading bulbs, after only 2 tries I found a match! This is the only place in the car where you will see the difference in colour as the bulbs are next to each other. Everywhere else will not matter!

    IMPORTANT NOTE: It seems that the DIS may work with a tolerance. I can use 150 Ohm resistors in the number plate set-up but it seems others are having problems. If 1 resistor does not work then install a second resistor in the other fitment. This way you can double the current and fool the DIS.


    Why are LED’s a trouble to install?
    The installation part is not so difficult, in the most part it is just a matter of taking the filament bulb out and putting the new LED bulb in. The difficult part is getting the car to think there is a bulb there and to supply it power. Audi’s being Audi’s monitor every bulb in the car, if the car detects there is no power or very little power being used in a lighting circuit it will cut the power from it, hence switching the bulb off. LED’s use much less power than filament bulbs. This is why we put a resistor in the circuit to fool the car into thinking there is a bulb there and to send it power.

    Interior Bulbs
    Festoon and map reading, front and rear
    Remove the clear plastic guard by levering it off with a screw driver, it will unclip. Now you can see the first two festoon bulbs. Now lever off the dark plastic guard, you should see the two map reading bulbs. There are two screws near the top of the panel, remove them and use a screw driver to lever off this unit. Unclip the electrical wires so the unit is free from the car. Place this unit to one side.

    Now go into the back of the car, find the map reading unit and gently lever it off with a screw driver. Disconnect the electrical wire and place the unit to one side.

    You should now have the front lighting unit and the rear lighting unit in front of you.

    Remove all the old filament bulbs from the units. You should have six bulbs. Now look at the rear light unit, you will need to solder a resistor like shown below. This resistor is used to stop the lights being on very dim when they are meant to be off. Insert the 2 x flank LED bulbs in the rear unit and the 2 x 42mm festoon LED in the front unit. Now, in the front unit there is a little bit of difficulty getting the map reading bulbs to face down, this is due to the way they are designed. To get them to face down you need to push them in with a little force, making the metal spring part of the bulb holder bend back a little and then turn the bulb to be secured behind the plastic guard. Looking at the unit you will see what I mean. This is the interior ceiling LED’s complete! Reattach the units and test! If the festoons do not light up try turning them around, LED’s are omni directional and can only pass current one way.

    [​IMG]

    Foot well
    Use a small screw driver to pry the clear foot well light off. You will see the wedge type bulb in the casing. Unclip the power supply and remove the unit, do this to both the drivers foot well and passengers foot well. Remove the cream plastic guard, you do not need this. Attach a resistor as shown below. Only attach 1 resistor to either unit. Insert the 2 x wedge LED bulbs, 1 into each unit and reattach and test. Again, the same rule applies, if they don’t light up turn the LED’s around.

    [​IMG] [​IMG]

    [​IMG]

    Boot
    Do the same as the foot well and attach a resistor. I believe the boot bulb is used in the puddle light circuit, this is why we are putting a resistor here. Reattach and test.

    Exterior Bulbs
    Puddle Lights
    The puddle lights used the same style holder as the foot well but you can’t completely remove them. When you pry the clear plastic off you will see a cream coloured guard over the bulb, remove this with some pliers, be sure it doesn’t snap off into the door card or you will get a rattle! To change the bulb use a screwdriver to gently remove the bulb, be careful not to touch the positive and negative sides of the bulb holder with the screwdriver as you will blow a fuse. Once the filament bulb is out replace it with the wedge LED. Do this on both sides. If you have a 5 door the rear doors are more difficult. I couldn’t replace the bulbs in the rear doors as they were guarded by black plastic. I asked my dealer to replace the bulbs for me when I went in for an oil change, they had no problem in doing it.

    IMPORTANT NOTE: When installing the puddle lights be sure to secure the bulb in place with some duck tape. This is necessary as the LED bulb is quite loose in the holder and can fall out into the door card. The duck tape will insure this won’t happen. Getting a bulb out of a door card is a very annoying job!

    Number Plate Lights
    Remove the light units by using a small Philips screwdriver. Remove the old filament bulbs and attach a resistor to each fitment as show below, be sure the resistor is secured in place and has a gap from the bulb as it will get quite hot. Insert the 2 x 36mm festoon LED’s into the light units, 1 in each, reattach and test, again, if one does not light, turn the LED around.

    [​IMG]

    IMPORTANT NOTE: The number plate LED mod has not been without a few problems. When the resistor is wired in this setup it is passing current a lot of the time. Due to this it can get hot! When i was testing with the 100 Ohm and 120 Ohm resistors it managed to melt the LED bulb and stop it from working. I am now trying with a 150 Ohm resistor, this will only be outputting 0.96 watts of heat. I am still testing to make sure this does not melt the bulb, I am confident it will be sufficient this time! We use 2 resistors in this set-up as only 1 can trigger a bulb warning fault on the DIS. Having 2 resistors in the set-up ensures that there is enough current being drawn to fool the DIS into thinking there is something there!

    IMPORTANT NOTE: I have just purchased more 36mm festoon LED's off eBay. They are made of metal, not plastic. I believe they can handle the heat a lot better than the original LED's i used. I advise purchasing these LED's over the plastic ones. This is what they look like:


    [​IMG]

    There! You are done! Now sit back and wait for it to get dark and marvel at your gorgeous lighting setup!

    The end set-up:

    [​IMG] [​IMG] [​IMG] [​IMG]
    #1
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  3. S3 LTN
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    S3 LTN Guest

    [Nov 21, 2008]
    Thanks for the write up Toby.

    How much did the lighting upgrades cost? Bulbs and resistors.....
    #2
  4. boggym
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    boggym Member

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    [Nov 21, 2008]
    Great write up Toby. Gives me something else to occupy my mind for modding projects. Will be carrying this one out for sure.
    #3
  5. tobycruse
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    tobycruse Member

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    [Nov 21, 2008]
    Erm, good question! I would say around the £50 mark.
    #4
  6. Astakos
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    Astakos Member

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    [Nov 21, 2008]
    Excellent write up Tobby!!
    I will surely try it and see how it goes.

    Thumbs up mate!!:icon_thumright:
    #5
  7. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Nov 21, 2008]
    I am in the middle of doing this mod too, in a bit of a different way. Going to get cracking properly next weekend though.

    I have got a peice of circuit board covered in copper to mount the resistors on, this should help deflect the heat nicely.

    I was also thinking you could use PC board fans for this mod if it's in an area with enough room. I found a fan in maplin that was 40x40x20mm and the current draw was about 1A which is pretty much perfect, plus it would do the opposite of getting hot! They're not cheap though at £5.99 each, compared with 18p for a resistor.

    Omni directional means in more than one direction by the way, you mean unidirectional, just so no one gets confused. Although it depends on the type of LED.

    Now I can see how you have attached the resistor to the number plate light holder I am going to get a couple of 330Ω resistors and attach one to each. The combined resistance will be 165Ω and the heat will be half as much in each. If this works I let you know. If not I already have a 150Ω waiting.
    #6
  8. S3 LTN
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    S3 LTN Guest

    [Nov 21, 2008]
    Excellent mate. Will order them in and have a crack at it.


    Staz have you been local lately? (Bedford)
    Not far from each other so if you ever free i'll drive down for a little helping hand. I'm not an ideal person to hold a soldering iron :uhm:

    Cheers mate.
    #7
  9. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Nov 21, 2008]
    No mate I have been in North Wales at my mum's for 2 weeks then go back to work in N. Yorks until xmas. I hope to have it all done by then but I can help you out if you need it :icon_thumright:
    #8
  10. tobycruse
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    tobycruse Member

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    [Nov 21, 2008]
    Hi Staz, thanks for your comments, any help is good help!

    How do you plan to use this PCB, could you post a picture of what you mean?

    Interesting idea to use fans, and yes, they wouldnt make any heat. But, they would make noise, especially fans that small. Where abouts would you put them? They would have to be mounted securely.

    Thanks for the unidirectional thing, i have amended the post!

    I see what your saying about using 2 resistors, the heat would be half as much each. But the total heat would be the same. It would be interesting to see if this worked as the space is quite small. I have two 330 Ohm resistors waiting if my current 150Ohm setup doesn't work! I have also ordered 4 more 36mm festoon LED's which seem to look more sturdy, incase the current LED's don't hold up!
    #9
  11. MarcQuinlivan
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    MarcQuinlivan Active Member

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    [Nov 21, 2008]
    I ordered up the bulbs on Monday so they should arrive on Monday or Tuesday. Thought they might arrive today, but it didn't happen.

    Might pop into Maplin tomorrow to pick up a couple of resistors.
    #10
  12. N8
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    N8 Kowalski Details VCDS Map User

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    [Nov 21, 2008]
    Thankyou very much toby, super post!
    #11
  13. N8
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    N8 Kowalski Details VCDS Map User

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    [Nov 21, 2008]
    It was my internet marc
    #12
  14. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Nov 22, 2008]
    The board is a big plate which I'm going to cut into smaller pieces and then mount the resistors onto. Although I won't do that initially with the numberplate ones as I will try the resistor on both first.

    I have decided against the fans because of the room needed for them. You would need to mount them somewhere where they had through flow and that becomes more complex than it needs to be. I was thinking about some sort of spacer on each corner and sticky pads to mount them. Resistors are the way forward though.

    The total heat would be the same for a resistor on each bulb holder but as they are separated it would be a lot better.
    #13
  15. S3 LTN
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    S3 LTN Guest

    [Nov 22, 2008]
    Excellent mate. No probs. Will have a pop at it see how it goes.
    Vast improvement never the less with this upgrade. :icon_thumright:
    #14
  16. tobycruse
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    tobycruse Member

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    [Nov 22, 2008]
    That is true. I will let you know how the 150 Ohm setup goes. If this fails, i will try the 2 x 330 Ohm that you suggested. The only thing i am worried about is the resistance in that setup. It will total 165 Ohm. I had a random number plate bulb fault the other night, possible because i was mucking around with the footwell lights, i don't know. I restarted the car and it went away. 150 Ohm could be the max resistance we can use...... Hope it isn't!
    #15
  17. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Nov 22, 2008]
    I will have some of the copper plate left over which you can have some of too. I have a plan for the footwell light setup, if it works I'll post pics.

    Well yeah exactly I don't know if 165 will be ok but there's one way to find out :icon_thumright:. If not then we could try something lower so the total resistance may be lower than 150 but the heat is still split in half.

    The footwell lights wouldn't cause a number plate light fault though.
    #16
  18. S3 LTN
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    S3 LTN Guest

    [Nov 25, 2008]
    Hey guys,
    How the 150 Ohm resistors doing on the number plate lights?
    Any issues?
    They the best choice to go for then....
    :icon_thumright:
    #17
  19. kettle
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    kettle Member

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    [Nov 26, 2008]
    well done, very helpful

    keep us updated on the number plate situation.
    #18
  20. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Nov 29, 2008]
    I haven't been online all week. I still plan to do my lights this weekend so I'll hopefully post pics and results on sunday on this thread.
    #19
  21. tobycruse
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    tobycruse Member

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    [Nov 29, 2008]
    The original post has been updated with some important points.

    1st: When doing the puddle light be sure to secure the bulbs with duck tape.
    2nd: In regards to the number plate light, i have found some LED's off ebay that are made of metal! See picture in guide. The metal LED's + the 150 Ohm resistor = no number plate problems!
    #20
  22. tobycruse
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    tobycruse Member

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    [Nov 29, 2008]
    For me the 150 Ohm resistor with the plastic LED is working fine without any melting issues. The DIS has come up a couple of times in regards to a number plate bulb fault but if you switch the lights off and on it goes away and does not return. I believe that 150 Ohm is the max we can use in this set-up. As for everything else, please read my revised "how to" guide. Everything is in there!
    #21
  23. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Nov 30, 2008]
    Right I'm not in the workshop looking sorting out my LEDs amongst other things. I have tried using a 150Ω on the footwell lights in the exact way you have done in the pics but it's the same as if there is no resistor at all. IE the lights come on for about 5 seconds then go off. I have checked the resistor and it's at 149.5Ω so I'm scratching my head right now!

    I even tried using 2x 220Ω (they were supposed to be 120Ω but the guy at Maplin gave me the wrong ones) and that does the same thing! And after a few tries the lights wouldn't come on at all!!! I had to put the bulb back in one side to get it going again.

    EDIT: Ok I thought I'd have another go with both but checked the resistance of the whole circuit with the LEDs and resistor(s) in place. With the 150Ω in the resistance was 150.5Ω and the LEDs turned off after 5 secs. With 220Ω in each side the total resistance was 108.5Ω and the circuit worked! I must have not put the resistors in properly the first time as I'm not soldering them in just yet.
    The resistors don't even get warm by the way :jump:

    EDIT2: Right all is finished now, finally!

    I have used the 2 220Ω resistors for the footwell LEDs (one in each obviously). I have soldered them in a slightly different position but it's essentially the same as Toby has done above. All works great.

    [​IMG]

    I found that I couldn't get enough play on the holders for the puddle lights to simply pull out the bulbs and fit the LEDs so I ended up taking the door cards off. How on earth did you manage that Toby??

    [​IMG]

    For the number plate lights I ended up having to use 2 150Ω resistors. I tried soldering them but the bulb holder acts as a massive heat sink so I just wrapped the legs around the base of the clips and again all is good. They get fairly hot but nothing major.

    [​IMG]

    A massive thanks again for your pics and write up Toby. They really helped me along the way :hi:
    #22
  24. ckh
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    ckh Member

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    [Nov 30, 2008]
    any links in buying which ones of ebay? so many!!!!!
    #23
  25. Boydie
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    Boydie Guest

    [Nov 30, 2008]
    Do you have to wire resistors? can you just not get the same bulb model number but in blue/white/xenon look?
    #24
  26. tobycruse
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    tobycruse Member

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    [Dec 1, 2008]
    You can. But it wont look the same as an LED setup. If you want the white LED look you need white LED's.

    Staz, in your number plate setup, did you use a 150 Ohm resistor in each light?
    #25
  27. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Dec 1, 2008]
    Yes mate. just one 150 wouldn't work and nor did 2x 220 (so 110 total) so I tried 2x 150s and it works fine!
    #26
  28. A3_3.2_S-Line
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    A3_3.2_S-Line Member

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    [Dec 2, 2008]
    #27
  29. JohnS3
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  30. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Dec 2, 2008]
    That won't work mate. I had to use 2x 220 ohms for the footwells, one on each. That made to combined resistance 110 ohms. The 150 on it's own didn't work so I would have tried 1x 120 ohm but the guy gave me 220s instead so I tried 2 of them and it worked.
    #29
  31. Fast,not furious
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    Fast,not furious Dealing with an OCD

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    [Jan 14, 2009]
    I've managed to find all of the bulbs on ebay,except the 168 194 refractor wedge for the puddle lights.

    Does anyone have a link for them? I can't find ones with a 9mm base and 10mm diameter to fit the holder - i removed the OE one from the boot to check sizes,i guess it's the same bulb for the puddle lights?

    Cheers
    #30
  32. benw123
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    benw123 Moderator

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    [Jan 15, 2009]
    That's great work. Any plans to do the sidelight, brake or indicator bulbs yet? I'd be interested to see what resistors would be needed since the bulbs are higher watt.
    #31
  33. mac1403
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    mac1403 Member

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    [Mar 14, 2009]
    DON'T use this guy!!. I did and he is very helpful until the bulbs come and don't work. Then you will not even be able to get a reply off him. He states that all his bulbs draw the same current as standard bulbs. I found they did not and to add to the woe they are the wrong type to give a good spread of light. When his pack arrived there wasn't even enough bulbs to do the rear map lights as well. The only part I can say which works so far is the number plate light, which consists of a flat bank of 6 leds attached to a standard festoon bulb and what looks like a resistor wired across. I haven't had time to check the heat from it, but after 10 minutes the plastic cover wasn't even warm.
    #32
  34. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Apr 15, 2009]
    Just a quick update. One of my numberplate LED bulbs gave up the ghost the other day. Just been out to replace it with a normal bulb and found that gradually the heat from the resistor had misshapen the LED and the end cap had come loose.

    Not sure I can be bothered to change it and position the resistor differently as I don't think it made that much of a difference. I'll have to wait until it's dark.
    #33
  35. scottie123
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    [Apr 15, 2009]
    Were these the metal ones staz?
    #34
  36. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Apr 15, 2009]
    Resistors you mean?

    Normal ones like the ones above
    #35
  37. mac1403
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    [Apr 15, 2009]
    The link for the Ebay item a couple of posts above is a complete set of led's. The interior led's are **** but I will say tat the No plate leds are great and do not require a resistor as it is already built in. If you email him he will give you a price and just email the No plate led's
    #36
  38. Jamiekip
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    Jamiekip Member

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    [Apr 15, 2009]
    Is there anywhere you can just buy the bulbs for the interior?

    Interioir lights front
    map lights front
    Interior lights back
    Footwell lights
    Puddle lights
    #37
  39. Staz
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    Staz is a retronaut Staff Member Moderator VCDS Map User

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    [Apr 15, 2009]
    Thanks but if I do it again I'll just position the resistors better or wrap something around them to insulate them. It all worked great how it was.
    #38
  40. scottie123
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    [Apr 15, 2009]
    no, i meant was the led the metal style?
    #39
  41. mac1403
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    [Apr 15, 2009]

    There are loads for sale on Ebay, but they are mostly from Hong Kong or the States. The main problem I found was refractor style led's are wider due to their design than the standard wedge festoon bulb. This gives you a real headache when you try to fit them. So to get them all the way in you have to bend the contacts. I have done all mine now except the puddle and boot led. These are doing my head in and I can't get answers to anything from anyone on here who has done the whole thing. Must be on the ignore list LOL
    #40

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