E92/E93 LED front turn signal (PY24W) DIY conversion
LED turn signal modification for pre-LCI E92, E93 headlamps
Published by Imperator
E92/E93 LED front turn signal (PY24W) DIY conversion
2006-2010 E92 and E93 cars use a BMW-specific bulb fitting in the front turn signal/running lamp housing. This bulb is referred to as a PY24W, which is an amber-glass, single-filament bulb. Some cars, including the M3, were delivered with a PY24SV (Silver Vision), which features a light silver coating around the bulb to reduce the visual "egg yolk" effect in the housing.
I will attempt to describe the process to convert your OEM PY24W bulb to a LED type fitting, using a few simple tools and LED retrofit bulbs intended for use on domestic vehicles.
The LED bulbs I am using were sourced from HIDguy.net, one of the few vendors offering the 5202 (H16 / 9009) type bulb. This is normally found in fog light housings of the GM GMT900-based SUVs, the Ford Mustang GT500 and the Pontiac G8 GT.
This 5202 LED fitting is manufactured by R-Tech Lighting and does not carry any specific branding. It is constructed with 18 SMD-type LEDs, is NOT polarity-sensitive and is available in amber, white, red or blue for $40/pair. For this DIY, I have chosen the amber color. Note that the white version is slightly brighter than the amber version.
Please note this modification WILL PERMANENTLY DAMAGE your OEM PY24W bulbs! There is a "point of no return" in this modification if you wish to keep your factory amber bulbs. I apologize for the lack of pictures to better illustrate the steps, but I got ahead of myself and didn't expect to finish this up so soon. I've attempted to word this DIY as carefully as I can to make this easy on everyone.
You will need the following tools to complete this DIY:
8mm socket wrench and/or nut driver
Professional/bench-grade soldering iron (40W or greater)
Micro butane torch (optional)
General-purpose rosin-core solder
Flathead, jeweler's screwdriver
Dremel Tungsten Carbide Cutter bit (part 9901)
Dremel 1 1/4" fiberglass cut-off disc
Plastic epoxy (optional)
Begin by removing the OEM PY24W bulbs from the headlight housing. To do this, you will need access to the back-corner of each fixture, through the wheel well.
Turn your steering wheel to the opposite side of the car which you will be working on. Turning to full-lock left or right should give you enough clearance to get your hands into the front of each wheel well.
With your 8mm socket/driver, remove four screws along bottom portion of the front fender liner. One screw is located underneath the corner of each front bumper, nearest the wheel well. Two screws are located inside the fender liner on the bottom and the last one is just a little farther up the wheel arch, just inside the front reflector portion.
Carefully peel back the plastic fender liner and reach in to the corner of the headlight housing. Use a flashlight to verify the position of front corner bulb cover. It is a round cover, approximately 4" in diameter with a flat handle edge.
Turn the corner bulb cover 1/4-turn counterclockwise and with a firm grip, wiggle the bulb cover back and forth to break the seal. Carefully remove the assembly from the headlight.
Remove the PY24W bulb base from the headlight cover by twisting 1/4-turn clockwise.
Repeat on the opposite side of the car.
The OEM PY24W bulb you will be modifying should look like this:
What we want to do is CAREFULLY remove and recover the copper bulb contacts from inside the bulb base.
Use a hot soldering iron and/or precise mini butane torch to melt the solder leads from the contacts to the bulb. You may burn some of the plastic around the inside of the PY24W bulb base--this is okay as you won't be using this bulb base again, but BE GENTLE with the copper contacts-- you want these in pristine condition to use with the 5202 LED base.
Work your iron and/or torch into the edge of the contact while using a small flat-head screwdriver to pry up on the bulb from the top of the base. Work the screwdriver between the black plastic PY24W base and the gray plastic base of the glass bulb. This will help to separate the bulb while reducing stress on the copper contacts. When this is complete, you should be able to pry the entire glass bulb from the black plastic PY24W base.
With the glass bulb removed, you can now pull the copper contacts out of the PY24W base by pressing in on the small lock-tabs around the outer edge of the base. The copper contacts should just fall out of the base at that point, leaving you with a bare piece of plastic:
EDIT: Alternatively, you can cut away the contact at the solder joint of the bulb, but you will need to retain the portion of the contact that fits over the plastic post in the base. This will allow you to simply pull out the copper contacts from the PY24W base without getting crazy with the torch or soldering iron. It should save you about 5-10 minutes of work.
Attach the Tungsten Carbide Cutter bit to your Dremel and begin grinding away at the inner plastic "plug" portion of your new 5202 LED base. You will see how this bit of plastic differs from the OEM PY24W base and will prevent you from fitting it to the round headlight plug. Be careful to remove only the inner rectangular portion of plastic, grinding down about halfway into the base, or just below the "window" slit surrounding the 5202 base. It won't look pretty, but you don't need it to look pretty right now.
When complete, attach the 1 1/4" fiberglass cut-off disc and grind down the metal posts of the contact prongs on the 5202 base. Try to make these posts even with the plastic socket surround that you just ground down. Use the cut-off disc to carefully notch the areas where the copper contacts will hang over the base, at the 6-o'clock and 12-o'clock positions. Use your bare PY24W bulb base to compare.
Carefully cut off the thin edge of each copper contact where it was once soldered onto the amber glass bulb. You can cut this down to the edge of the larger hole that was used to fit into the plastic post of the PY24W base. This will be your solder contact with the post of the LED bulb.
Fit each copper contact into your modified 5202 LED base, using a small screwdriver to make sure each copper contact is firmly pushed into the base and is making contact with the LED posts. MAKE SURE THE COPPER CONTACTS ALIGN WITH THE POSITION OF THE OEM PY24W BASE. The contacts should be at the 12-and-6 o'clock positions, snugly against the outer portion of the 5202 base.
Use your soldering iron to affix the copper contacts to the posts. Your finished product should look something like this:
Take a moment to compare your newly-modified LED bulb base with the OEM, BMW PY24W base. You should note where the contact aligns at both bases.
Take the 4" round outer headlight housing plug that you removed from the PY24W bulbs earlier. Note the rectangular black plastic post in the middle. Use the Dremel and cut-off disc to cut this post halfway down. You don't need this post at all with the new LED base, but everything should fit together by chopping off a couple millimeters of this plastic center post. Be careful not to grind away any of the outer tabs on this plug.
Test-fit the modified 5202 LED bulb base with the outer headlamp housing plug. It should fit into the plug and turn 1/4 counter-clockwise, locking into place. If it doesn't fit right, make comparisons to the OEM PY24W bulb base.
Once you're happy with the fitment, use plastic epoxy to seal the solder joint and copper contacts to the bulb base. Use the epoxy sparingly so you don't run into any clearance issues with the round housing plug that the LED base needs to fit into.
Time to install your new LED signal bulbs!
Note that the LED array is NOT polarity-specific so you don't have to worry about orientation when fitting to the car, but you must be mindful of the bare copper contacts when installing into the headlight housing. You can easily bend or break these contacts if they don't align into position with the prongs on back of the headlight housing.
Once installed, your new LED signal bulbs will look like this. I took this picture with the parking lights on, at half-dim intensity:
Unfortunately, I found that the amber LED bulbs aren't as bright as the OEM PY24W halogen bulbs, but they're definitely noticeable and provide enough contrast/illumination to see the signal. It is possible the white version will be brighter, if it isn't washed out in daylight.
Also note that YMMV regarding the bulb-check and control check of the car. My 2010 is fitted with 50W resistors in the turn signal portion of each taillight, used with a set of very bright LED turn signal bulbs. To my surprise, I did not receive any faults with these LED bulbs installed and the car passed the check control in iDrive. There may be enough internal resistance in the LED towers to "fool" the DME during the bulb-check procedure. It's also possible I need to drive with these longer before a fault is generated. If you do encounter a bulb-out error, you can remove the bulb-check procedure with independent coding.