1 Although you can access the headlight assembly with the wheels on and turned hard to one side, I find it easier to just jack the vehicle up and remove the tires. Once you remove the access plate in the wheel well liner, you need to remove the back of the headlight assembly by pulling the retaining bail down from the two points that it is engaged in the circled notches. You may need a screwdriver to free the retainer. Once it is fully lowered, some artful manipulations should allow you to remove the headlight backing plate.
For reference, this is the driver's side. The passenger side will be the reverse layout.
2 The daytime running light is the inner halo, here on the driver side it is to the right. Remove the brown and white wired connector from the rear of the bulb assembly. It is not latched, but it may require needle nose pliers and a bit of force to remove. Then remove the bulb assembly by twisting counter-clockwise. Note that there is no need to loosen or remove the T20 torx bolts. Ask me how I know- I lost one deep inside my front bumper area and it took the better part of 2 hours to find and retrieve it!
3 The factory DRL bulb is a simple 10W halogen with a BA9S base. However the plastic assembly is such that there is no way to remove the bulb. BMW wants you to buy the 50¢ bulb along with the $30 assembly as a single unit!
4 The solution is as easy as taking 10 seconds with a dremel tool to make two little notches next to the bulb to allow the bayonet pins to slide out.
5 Once I removed the bulb I cleaned up the dremeled notches a bit with a micro-file
6 This is the hi-intensity LED bulb I ordered off ebay from China. I could not find anything even remotely equivalent in the US. Claimed output is 500-600 lumens and it arrived amazingly within 1-1/2 weeks. Remember to make sure you use a true BA9S bulb which has pins 180° from each other. These are different than BAX9S bulbs used in some vehicles that have pins 150° offset.
Note that these bulbs are not "error free" and you will get a "bulb-out" indication on the dashboard. I will be following up with the steps I take to recode my light control module to ignore the DRLs and eliminate the bulb warning.
7 This comparison shot is in bright mid-daylight with the sun almost directly over my left shoulder. The left passenger side is the factory halogen DRL and the right driver side is the LED bulb.
8 Same comparison with the car partially pulled into the garage to provide some shade. Left side is factory halogen, right side is the LED.
9 Same shot as before with the Xenon HID headlights turned on for comparison.
10 Parking lights on at night
11 A couple of weeks after I installed the first set of LED bulbs, I discovered even brighter ones that used the latest Cree XBD emitters x10. The Cree XBD chips have higher efficiency, run cooler, and have better hi-temp toleration than any of the prior generations. The bulbs were also a little pricier at approx. $32 / pair from China off of EBay. Once I received the bulbs, I realized that I needed to file down the center contact by about 1mm in order to fit them into the bayonet socket. Otherwise the bulb could not be inserted far enough to lock it into place. You can see the bulb on the left with the filed down contact compared to the one on the right. I should also add that these bulbs are much better constructed than the previous LED bulbs I ordered.
12 Here's the comparison against the first set of LED bulbs that I previously tried. The new bulb is on the left / passenger side. It is clearly brighter than the right / driver side.
13 Final result in full summer midday sun
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