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LED Interior light bulbs fitted - footwell, centre and map lights

Discussion in 'A3/S3/Sportback (8P Chassis)' started by mattandrew, Sep 11, 2008.

  1. mattandrew
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    mattandrew Member

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    Footwell Lights
    A few months ago I started to install some LED lights in the footwell lighting, first I installed the passenger LED and it worked fine but when I installed the drivers they both went out. This caused an error in VAGCOM, must of been to do with current draw or something similar. For the last 3 months I have had one normal bulb and one LED. Been having a play around tonight and not sure what I did to sort the problem but they both now work. I had a play in VAGCOM but didnt change anything. I also found a setting in VAGCOM to make the footwell lights brighter

    Heres how they look

    [​IMG]

    This is the bulb I used, its the wedge type as used in the side lights. The reason I used this type of bulb is because it directs the light out of all four side and the end of the bulb. A lot of the LED wedge bulbs only have the led's in the end of the bulb, this is no good for the footwell as the light given off does not shine through the lense and into the footwell and it is very dim.

    [​IMG]

    Here they are on ebay £5.70 delivered for two, same seller I purchased from
    http://cgi.ebay.co.uk/2pcs-501-W5W-...39:1|66:2|65:12|240:1318&_trksid=p3286.c0.m14

    Main light and map reading

    [​IMG]

    I used two LED festoon bulbs for the main light and they work a treat, you can either use 42mm or 44mm festoon bulbs

    [​IMG]

    £8.50 for two delivered
    http://cgi.ebay.com/1pc-264-Festoon...photoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

    The map reading lights were a bit more tricky, the problem was finding a bulb which would direct the light down, the first couple of bulbs I tried looked ok but did not give enough glow as the LED was in the end of the bulb.
    Heres the bulbs I used, as you will see the LED is on the side of the bulb

    [​IMG]

    When the bulb was first inserted the light shone to the side as the locating pegs were in the wrong place on the bulb, I managed to slide the plastic behind the bulb holder back, turn the bulb and jam it in place. It makes more sense when you have a closer look at the fitting, it been in place a few months now with no problems.

    Heres mine same seller £9.10 delivered for 4 delivered
    http://cgi.ebay.co.uk/2pcs-BA9S-T4W...39:1|66:2|65:12|240:1318&_trksid=p3286.c0.m14


    Or these £11.70 for 4
    http://cgi.ebay.co.uk/2pcs-BA9S-T4W...39:1|66:2|65:12|240:1318&_trksid=p3286.c0.m14

    Rears
    When I changed the rears (same bulb as front map lights) I had issues with all the interior lights been on very dim, even when all doors are shut, at the minute I still have the standard bulbs in the rear. Think if i install a resistor on the rear supply it may solve the issue.

    Nnmber plate
    36mm festoon like these, two for £6 delivered
    http://cgi.ebay.co.uk/2x-XENON-WHIT...hZ008QQcategoryZ72237QQtcZphotoQQcmdZViewItem
    Ive not fitted them yet as they may need a resistor in line, ill let you know how I get on.

    For under £30 you can get the full setup - footwell, map, centre, rear and number plate


    Matt

    :thumbsup:
    #1
  2. s8craig
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    s8craig Active Member

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    Resistors go in parallel with the bulbs to balance the current drain. If you put them in series you would reduce the current drain by increasing the overall resistance and decreasing the load.

    Basically the resistor draws the current a normal bulb would have drawn and fools the cars monitoring systems to think a normal bulb is installed.
    #2
  3. RobinA3
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    RobinA3 Active Member

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    Craig are the footwell lights plug and play meaning no need for resistors?
    #3
  4. s8craig
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    s8craig Active Member

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    It would depend if the monitoring circuit "if it has one" is fooled by the new bulbs.

    The fact that Matt had one original lamp and a LED lamp at first says it's borderline.
    #4
  5. tobycruse
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    tobycruse Member

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    Just bought the festoon, map reading and number plate LED's. If the normal bulbs are 5W and they are running off a 12v supply the current draw is 0.42A. So, doing the sums, you will need a 28 Ohm resistor in there to mimic the bulbs draw. But, with this resistor in parallel will it stop the LED's being on slightly?
    #5
  6. MarcQuinlivan
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    MarcQuinlivan Active Member

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    Looks good Matt. Might invest in some of those.

    We didn't seem to have enough numbers for the Bimmian group buy I was trying to organise so discounts would have been minimal.

    might wait until you sort the number plate bulb first to see how it looks and then buy the whole lot together.
    #6
  7. mattandrew
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    mattandrew Member

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    which bulbs did you buy, did you get the ones I listed?


    Thanks!

    I have fitted one of the number plate bulbs and it looks good but when i fit the other they both go out and the bulb error comes on. I did try and fit a resistor is parallel on one of the bulbs but I think its resistance was to high (100 ohm) It did the trick and both leds light and no error but after been on 10minutes the resistor must of been glowing red as it started to melt the festoon bulb - (they have a plastic lens - the resistor wasn't touching)
    Not sure if a smaller resistor ie 6ohm would get as hot? I did speak to the guy at the electronics shop and he gave me a 6ohm one but it was big in size (10mmx20mm) He said as there was a constant flow through it needed the heat sink.
    When ive got time I might fit the resistor behind the panel in the boot or try a smaller resistor - 6 ohm in the bulb holder
    #7
  8. tobycruse
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    tobycruse Member

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    I did get the bulbs you listed, i am awaiting delivery of my S3 to fit them. On the map reading bulbs is it easy to move the plastic back? I am worried about breaking something!
    #8
  9. gr1zly
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    gr1zly Member

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    Yesterday I've instaled Led bulbs in my car, and I saw one problem the footwell bulbs are lighting only 5 seconds and then they are off... Any suggestion what can I change?
    #9
  10. tobycruse
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    tobycruse Member

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    This problem comes back to resistors. The car "thinks" there isnt a bulbs there due to the high resistance of the LED bulbs, hence stops the power supply. What we need to find out is what current needs to be drawn to tell the car there is a bulb there! Has anyone got some spair resistors they can put in parallel to find out? The normal bulbs draw about 0.84A, i wonder if 0.1A would be enough?
    #10
  11. tobycruse
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    tobycruse Member

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    Ok, i have just ordered several 120 Ohm and 100 Ohm 2W resistors. I believe putting these in parallel will cause the car to think there is a bulb there and keep supplying power! Watch this space!
    #11
  12. gr1zly
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    gr1zly Member

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    But is there any bulb company that makes LEDs with resistors?
    #12
  13. tobycruse
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    tobycruse Member

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    No that i know of. Though i have had an idea. It would be possible to solder the resistor directly to the outside of the bulb, making it a neat and tidy job and then you could put the bulb in place and the system would work. As soon as i get the resistors i am going to give this a go!
    #13
  14. Staz
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    Staz is a retronaut Staff Member Moderator

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    Just did the maths without realising you had already done it. You're right though, you need a 28ohm resistor that handles at least 5w.

    Maplins do a 22ohm at 7w. The next one up is 47 so the 22 is the best you're going to get (unless you want to start combining other resistors!).

    http://www.maplin.co.uk/Module.aspx?ModuleNo=2179
    #14
  15. mattandrew
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    mattandrew Member

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    I would be VERY careful with the 100 ohm mate, I put a 100ohm resistor in parallel with my number plate LED festoon and it got that hot it melted the plastic LED casing - it wasn't even touching. Saying that im not sure what wattage the resistor was


    As i said before becareful



    Ive got a resistor from a similar shop but its quite big so may need to install somewhere else in the circuit


    Regarding the light coming on then going off I had this issue at first but now it seems to be ok and I have no resistors in place
    #15
  16. scottie123
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    scottie123 (●̮̮̃•̃) (●&#

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    Has anyone else had problems fitting the led wedge bulbs in the footwells?
    I have tried, but due to the size of the wedge, the wont contact properly of be very secure. Had a look at your ebay link mattandrew, and they appear to be the same size as the ones you have fitted.

    Am i missing something here? :)
    #16
  17. tobycruse
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    tobycruse Member

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    Once fitting the LED map lights and closing all the doors you can see that the LED are still vey faintly on. This does get annoying at night driving and makes you LED improvement look like a half assed job. This is how to resolve the dim light problem.

    1st, remove the rear light section from the roof lining.

    [​IMG]

    2nd, on either side, NOT BOTH, solder a 2W 100Ohm resistor in parallel in the lighting circuit like shown below.

    [​IMG]

    3rd, reattach the unit and test.

    If all goes well the LED's should switch completly off when all the doors are closed!
    #17
  18. N8
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    N8 Kowalski Details

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    So when you doing mine Matt? :arco: I'll give your a car a fresh up, you sort mine out :sly:
    #18
  19. mattandrew
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    mattandrew Member

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    How hot does the resistor get, have you left the light on for say 5 minutes with the light unit out and checked the temperature of the resistor?
    #19
  20. ckh
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    ckh Member

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    do u need the resistors for the number plate light?
    #20
  21. tobycruse
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    tobycruse Member

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    If it works on a the same type of system, yes. I am looking to do this next! Watch this space!
    #21
  22. tobycruse
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    tobycruse Member

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    The resistors gets fairly hot, but nothing serious. Its a 2W resistor and it has about 1.45W going through it. If you imagine the casing is made to hold a hot 10W bulb, its going to be ok!
    #22
  23. tobycruse
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    tobycruse Member

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    Just put the number plate LED's in place and the DIS came up with a bulb fault. I then removed one of the bulb holders and placed a 100Ohm 2W resistor in parallel and connected it. The DIS still came up with a fault! I then removed the same holder and turned the LED around, it then all worked (LED's are omni directional). I did not test it without a resistor, but if it works on the same system as the rest of the car it will not work without it.
    #23
  24. mattandrew
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    mattandrew Member

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    I did the same (not sure what watt the resistor was but it was 100 Ohm and it worked BUT I then left the sidelights on for 20minutes and came back and felt the lense it felt quite hot, so I removed the housing and found that the plastic bulb lense had started to melt and distort (originals are glass). The resistor was not in contact with the festoon bulb but still melted the festoon lense
    #24
  25. ckh
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    ckh Member

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    hi

    can anyone confirm which resistor to use for the number plate led's? i don't want to start trying the wrong one

    thanks
    #25
  26. tobycruse
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    tobycruse Member

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    Ok, this is a bit of a test at the moment! I am currently running a 2W 120ohm resistor and its ok. The resistor i had before was only a 100ohm and it got too hot and melted the LED bulb. I have got a selection of resistors and i am hoping to test the system to see what the highest rating you can put in is. As higher ohm's means less heat = no melting bulbs! So watch this space!
    #26
  27. ckh
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    ckh Member

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    thanks for the update!!
    #27
  28. Staz
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    Staz is a retronaut Staff Member Moderator

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    You could try using more than 1 resistor to spread the current flow and therefore the heat would be reduced.

    Or if you have a Maplins nearby get a variable resistor (high powered of course), then increase the resistance until the car detects it as an open circuit and then measure the resistance accross it and you'll know what sized resistor to get.

    I would like to try this myself by right now the nearest Maplins is about 50 miles away! And the postage would cost more than the products!!
    #28
  29. Digzz
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    Digzz "Started From The Bottom"

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    "mattandrew"

    I'm getting the same issue as you below...I was wondering if you know how to resolve this issue ? What Resistor do I have to use ?

    Footwell Lights
    A few months ago I started to install some LED lights in the footwell lighting, first I installed the passenger LED and it worked fine but when I installed the drivers they both went out. This caused an error in VAGCOM, must of been to do with current draw or something similar. For the last 3 months I have had one normal bulb and one LED. Been having a play around tonight and not sure what I did to sort the problem but they both now work. I had a play in VAGCOM but didnt change anything. I also found a setting in VAGCOM to make the footwell lights brighter
    #29
  30. Josh84
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    Josh84 Member

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    Hi all, quite new to the forum but having a problem with the Number plate lights. I had LED's in and they were working fine for a good 6 months, but 1 of them started flashing. So i have replaced them with new can-bus error free ones and they dont work. I decided to go back to the original filament bulbs that were in the car but now these wont work either and i have the error light on the dash. Does anyone know why these now wont work or what i can do to get rid of the error light? Car is a 2004 2.0TDI. Thanks
    #30
  31. poli84
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    poli84 Member

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    These are the exact LEDs that I have in my footwell (and puddle) lights in my MY10 S3.
    2x T10 194 168 5SMD 5050 LED Light Bulb Xenon White 12V | eBay

    Worked from the minute I installed them and have never had a problem with them.
    No errors, no flickering, no turning off, nothing. Perfect lights.

    [​IMG]
    #31
  32. Digzz
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    Digzz "Started From The Bottom"

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    Thanks....I've solved the issue with a 220 ohms resistor. :rockwoot: poli84 it's strange how yours work out the box without resistors as I have the same ones but in white. :think:
    #32
  33. mattandrew
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    mattandrew Member

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    glad you got it sorted digzz
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  34. poli84
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    poli84 Member

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    Yeah that is very strange.
    I read this thread initially before I installed and thought I was going to have problems.
    Another Aussie 8P owner used the same lights on his 3.2 and didn't have any problems either.
    Surely our cars wouldn't be different to yours in this regard.

    Glad you got it sorted though.
    #34
  35. Bugsy_27
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    Bugsy_27 Vorsprung Durch Technik

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    Nice mod Matt, these will be on my to do list for next month!
    #35

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