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LED Fog Light Bulb Resistors Fitting Guide

danb986 Oct 23, 2011

  1. danb986

    danb986 In awe of VCDS Team Daytona

    My project this weekend was to fit my cruise control bits and fit the LED bulbs and resistors to my front fog lights.
    There is already a good guide for the cruise control (thanks to Sijones and Avus Sportback) so I thought I'd do one for the LED Resistors.

    I bought some 68 LED H7 bulbs from ebay for about £3 and after waiting for the slow boat from Hong Kong, they eventually arrived. I was fairly certain that they'd throw up a bulb out warning on the DIS, so I fitted them and then turned off the cold diagnosis on the front fogs using VCDS. For reasons I still don't understand, the bulbs worked fine, but still showed a bulb out warning.
    After a bit of searching on this, I came across a thread that Silky had done on the same subject. I also discovered that he bought his from T8UPS, so I thought he was the guy to contact. After a few messages, Trups sorted me out a couple of resistors and I was in business again.

    These are the resistors I bought from him:

    I removed the front fog grilles by levering the grille down from the top with one screwdriver and levering up from the bottom with another. There are little slots, so it'll be obvious when you look. Please keep in mind that mine is just a Sport bumper, so it will be different on the S-line and S3 bumpers.

    With the grilles out, I undid the 3 torx screws holding in the fog lamp and pulled it forward. I unplugged the plug in the back of the unit by putting a small flat screwdriver in the gap in the side of the plug and gently lifting up the tab. The plug easily slid out. With the lamp removed I unclipped the cover at the back of the plug on the harness to allow me to remove the plastic sheath around the two fog light wires.
    After I'd got to the wires I stripped a small section of the insulation off of both of them.
    (sorry for the blurry photo, it looked fine on the screen of my camera :3sadwalk:)

    I then soldered the resistors wires to the exposed sections of wire and used heat-shrink tape. I hadn't used this stuff before, but it was amazing. Normally you need to be able to slide a tube of heat-shrink over the wire, but this isn't possible if you haven't cut the the wire and are only joining to it. The heat-shrink tape allowed me to waterproof the joint without having to actually cut any wires all the way through.

    After both wires were done, I replaced the plastic sheath and the cover at the back of the plug and tidied the wires with some insulating tape. You can see the cover at the back of the plug has been put back and also the sheath.

    I then had to find a mounting point that was away from anything plastic or flammable due to the resistors getting very hot. On both sides there is a horn, so I used the bolt at the back of each one. It was a T27 torx bolt and it was a bit fiddly to get to, but it was an ideal spot. The passenger side one had masses of space, but the drivers side one was a bit tighter. The only thing it gets near though is the washer bottle, but after a little bend of the bracket it had plenty of clearance.

    In the photos below you can see the back of the arrowhead shaped brackets that the resistors are mounted to. You can probably just see the gold resistors behind them.

    Drivers side:

    Passenger side:

    This is what it looks like with one done. They aren't at full brightness here. I've got my fogs set as DRL's and the setting that controls the dimming of them is turned down from 92 to 40. This means that they come on at 40% brightness as DRL's, but go off when you turn on your sidelights or headlights. If you then turn on the front fogs they operate at full brightness.

    Here are the finished articles (again running as DRL's)


    Brightness wise, they aren't as bright as the old H7 bulbs, but they are perfect as DRL's and look still pretty bright when running at full brightness. I can't imagine they'd be much use as a driving light and awful as a fog light, but that's not what I got them for. I never found my standard front fog lights to be much use in fog anyway to be honest.

    They even look OK with my headlights, which are halogens, but with Osram Nightbreaker Plus bulbs. If you've got xenons then they'd look even better. Check out Silky's thread for photo's of his.

    If you fancy doing this yourself then get in touch with Trups (T8UPS) and he'll sell you everything you need. He's extremely helpful and a real pleasure to deal with.
    Paullie likes this.
  2. slade777

    slade777 Member

    Cracking write up mate!!! I've got some off Trups and he's doing some for my mates car and once they come through will get them fitted on mine.
  3. Paullie

    Paullie Banana Menace! VCDS Map User

    Well done, Buddy! You did a great job there. I managed to find a set of H11 5W LED bulbs with projector lenses on them and a set of 50W 6 Ohm resistor packs with H11 plugs already linked up to the resistors themselves, so I don't even need to wire or solder them in, ..just plug and play (best thing for a girly like myself, lol!). I've just got to find some suitable brackets on which to mount the resistors. Hopefully I'll have them fitted in the next week or so. Great write up and well done again! Paula :wub: x
  4. Farhan

    Farhan Active Member

    Good write up dude been waiting on this! just a quick question where did you get that bracket to sit the resistor on as i want to mount my drl resistors down in that area but i have nothing to mount them on.
  5. danb986

    danb986 In awe of VCDS Team Daytona

    Thanks everyone.

    Trups supplied them with the resistors. I think they're a universal sort of thing, but they do the job perfectly. You could probably use the stereo mounting strips that places like Halfords sell, then you can bend them to get enough clearance from plastic parts. If not, then maybe have a word with Trups, he might be able to sort you out with some like the ones he supplied me.
  6. 1inchpunch

    1inchpunch Member

    Great write up danb986. Been waiting for this since you said you'd ordered some on Silkys thread. Quite fancy doing this but think I might wait until we get some fog so I can see if I actually use my fogs. Had them on all my other cars but can't remember if they made much of a difference.
  7. dipteshr

    dipteshr New Member

    I've just upgraded the fogs on my A4 B8 from the standard yellow ones with MTEC 4350K H11's and I have to say they're a good match. They are available in the UK and dont cost as much as the Hoen imports. I would suggest anyone looking to upgrade the fogs who doesnt want to mess around with resistors and wiring to use these.
  8. tdi-man

    tdi-man Well-Known Member

  9. Shady0808

    Shady0808 Audi S3 Essex

    So are fog lights H7 or H11? I have a S3 8P1 2011.

    I want to make sure my fog bulbs are road legal as fog lights that are not bright enough will fail an MOT
  10. SootySport

    SootySport Well-Known Member Team Silver

    I've never known an MOT tester to check the front fogs. Rear fogs , yes but not the front as many cars don't have them anyway.
  11. Shady0808

    Shady0808 Audi S3 Essex

    Yea I've had them check before on my previous car, told me to change them as they are not bright enough :wtf:
  12. downtothebone

    downtothebone Active Member Team Scuba Audi A3 Audi Cabriolet Owner Group S-line owners group

    I don't think front fogs are tested ... You must have at least one rear tho.

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