I just finished installing LEDs on my B7 Audi S4 and wanted to share some pics and a quick DIY if you want to do it yourself. Above I’ve pictured the before & after, as you’ll see you get rid of that yellow-ish halogen with a super bright & clean cool white color from the LED. It takes about 10-20 minutes to install and luckily you don’t have to remove the bumper or headlights to install, you just have to wiggle your hands a bunch.
Please note: this will only work for B7s with xenon headlamps – the halogen headlight housing does not have a DRL bulb (the high beams are located in the halogen housings where the DRL goes in the xenon housings). If you want to do a similar mod for your B7 equipped with halogen headlights, you’ll want to replace the city lights instead of the DRL bulbs – they’re the smaller bulb located in the upper corner of the inner housing of the headlight. It will be the same process except you’ll want to buy a 168/194 sized bulb for the city light (I like this 20 LED one on Amazon) and smaller 50watt/6ohm resistors (like this one). Alternatively, you could do both the DRL & City Lights if you have a xenon-equipped car, which is what I plan to do eventually myself…
Here’s what you’ll need for the conversion:
2 1156 Bayonet Bulbs (one for each side):
2 resistors (one for each side) – several different resistors work, and the consensus seems to be 5-10 ohms is what you’re looking for, with anything over 23 watts being fine – so here are two options to try. I’d order two of each and see which works better on your car, they’re cheap enough it doesn’t hurt. As you can see in the picture above I’m using 25W 15Ohm resistors and have had this setup for several years without trouble on my S4 (and my A4 before it). This article on DanPlanet suggests a 15ohm, 50W resistor is ideal, although these are harder to find – I think he has a valid point that you want to find a 50W resistor so that you’re not running too close to maximum tolerance.
The install is pretty simple as I said before. I followed this DIY on Tyresmoke.net but took some additional pictures to help out.
First, remove the plastic cap on the side of the housing, then pull out the stock bulb by turning it counter-clockwise. Be careful not to pull the wiring too hard or you’ll pull out the city lights too (the smaller bulb also pictured) which are very hard to remove. It’s a little tricky to get the bulb out but just be patient and if you have to, find a friend with small hands to help out For the passenger side you’ll need to remove the plastic air intake to access the side of the headlight, which is held in just by two phillips head screws. Here’s a pic of the bulbs taken out:
Next take out the stock bulb and plug in the LED bulb to the grey plastic base.
Next you’ll want to install the resistors. You’ll simply bridge the yellow and brown wires with the resistor connecting the two. It helps to strip a section of both wires so the resistor gets good contact (in theory those resistor clamps should strip for you, but I’ve found they often don’t get a good enough connection). Test to make sure the bulb works and resistor is working too (it will get very hot very quickly) before trying to put the bulb back in, as it’s a pain to wiggle it back into place.
Because the resistor gets very hot, I didn’t want it inside the headlight housing where it could melt other wires or even the headlight housing itself. So I kept the resistor outside of the housing and just kind of pinched the wiring in the cap. I then found a way for each side to tape our mount the resistor where it wouldn’t cause much trouble and stay cooler.
Just repeat for the other side and you’re all set!