So, you like the look of the newer LED tail lights but you've been told they don't work without the official retrofit kit with ballasts. Well, whoever told you that was very possibly WRONG!! If your car has a LCM II (e39s before MY99 that didn't replace the LCM), you would benefit from the retrofit kit as it's about the same price as a new LCM (LCM IV). However, if you have an E39 with an LCM III or newer, you can simply code your LCM to be the ballast that everyone charges a crap-ton for.
This swap requires:
- drilling new mounting holes in the car's light buckets
- hammering a little bit for clearance of the new light (different shape)
- inserting pre-crimped wire leads into a plug
- soldering some wires (please don't cheap out and use some universal crimp connector)
- Light Control Module coding via GT1, SSS/Progman, NCS expert,BMW Scanner v.1.40, or Autologic (there may be others)
NOTE: if you don't have the coding tools the regional sub-forums are tools of great value, and you can often find the computer coding tools you need.
Chassis Bashing:
The blue line is where you'll need to bash (2 minutes with a hammer for me) and drill *note*, I forgot the arrow pointing to the other lower mounting hole I drilled):
Fit comparison (after bashing) - OEM US facelift Celis lights:
vs. pre-facelift OEM hellas:
Electrons in motion (bench testing):
Not really sure why everyone asks the proper voltage for these lights, it's only printed on them.....(NOTE: LEDs are current driven devices, and to get the driving current we use P=V*i, or 1.2W/12V = ~108mA):
Unfortunately, all my power supply could muster was about 10.2V which was just enough to illuminate the LED tails, albeit under driven as seen below on the multimeter (only ~33 mA).
Take some adderall or something so you don't mix this up:
More wire prep, this time on the Celis plug (IIRC, this is also the right):
Planning to solder my Celis wires for the right side, and comparing WDS wire colors to actual - WDS was right, I just wanted to be careful:
Feeling cramped:
In-car workstation (400W inverter hooked directly to the battery to power the 40W soldering station):
Left tail light just before shrink wrapping the solder joints and re-looming the remaining wire:
Final testing - if you're wondering about the varied tail light intensity, the tail lights are just sort of propped up at different angles, i assure you they're the same (the pre-facelift lights are not actually on, that is just the camera's flash bouncing off the tail light lens)
They are installed now, my LCM IV is coded and everything is A-OK.
I did confirm that the LCM acts as the ballast via voltage and current measurements - 11.8-12.2V @ idle while the battery was at 14.2V.
any problems since the install?
What is the purpose of the ballast if the tails use a regular 12V supply?? The lcm works just like relays do but computer controller.
i did the same thing to my 97 and now every time i turn my car on my back LEDs flicker for a bit then it goes away looks kinda cool. Any idea why it does this?
Same thing happens on my '02 now that i put white LED instead of the halogen bulb for my angel eyes :/
the flicker is the LCM sending an additional pulse of current through the circuit to perform a bulb check.
You can turn this off by coding the LCM properly.
The early LCMs were not designed for LEDs and do not control the voltage in a tight enough range, thus the ballast was needed to do the voltage regulation and act as an error-code canceler.
Last edited by mattmartindrift; 05-11-2012 at 07:36 AM. Reason: Automerged Doublepost
108 ma and 33 ma. Im not getting it. Is the lcm monitoring the current draw on the circuit or the voltage on the circuit? Is the point to create a load on the lcm of 108 ma or that the voltage is at 12 volts loaded at the light? I understand that leds draw less current and i assume the lcm is looking at the current draw or voltage drop why couldn't you just add load to obtain the current draw or voltage drop if you didn't want to recode the lcm? I dont see why you couldn't use ohms law to manipulate the variable that the lcm is monitoring and simulate the monitored variable with resistors of the correct wattage? Just bouncing numbers around. If the bulb is a big resistor of say 3 ohms at 2 watts why couldn't you put a 3 ohm 2 watt resistor on in place of the bulb to eliminate the error? And with that said why if you added the leds to the circuit and they were 1 ohm 1 watt could you parallel a 2 ohm 1 watt resistor? To have the lights and no faults?
Im really just curious and havent really measured or looked up what kind of values you get out of leds. Im being lazy and hoping you will educate me without me having to do the calculations and gather real numbers.
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It seems like someone would make conversion plugs?
because it's much easier, cleaner and more reliable to use the OEM, built-in, digital regulation. if you wanted to swap your home lighting from incandescent to CFL or LED in an already-existing lamp, wouldn't you just get the type that screws in to an already-existing socket? Versus making your own transformer from cobbled-together, untested parts.
www.ecstuning.com sells them.
Last edited by mattmartindrift; 05-28-2012 at 01:08 PM. Reason: Automerged Doublepost
Sorry, im really interested in this. Not to flame or poke holes im really interested in understanding the lcm. I dont mind if you take an educated guess if you dont know for sure, i dont know for sure either but i think i know how this thing works but i dont want to be the guy spouting bad information if i have a chance to learn a little more. So you are replacing the original lights with led versions? You get an error on the dash after some period of time for the lights. On the later versions you recode the lcm and you dont get the error anymore? When you say ballast are you referring to something in the new light that converts the 12ish volts to whatever the leds need? For instance they used a bunch of 5 volt leds and the ballast is dropping the voltage from the harness to 5 volts. 12 ish volts in and 5ish volts out? The number could have been 24 ish on the leds. Different method but it will take my brain in the right direction.
matt, I am in the process of doing this DIY now. I hooked up my PAsoft 1.4 and i cannot figure out how to recode the LCM
I went into the LCM module, but cannot find anything relating to "LED"
(As of right now, it seems like the CELIS tail lights work just fine, just the right side brake light stays on, maybe this is why I need to recode the LCM)
Any help?
still trying to help - haven't had access to an LCM3-equipped car to see what is available in PAsoft.
I recently aquired celis tail lights and headlamps from a 2002 525i. My question is, if i get the LCM from the same vehicle i got the lighting from will i have to have the LCM coded?
Just bought some OEM Celis tails and am looking to do the retrofit soon...
They came with the plugs/pigtails, which I will need to solder to the old harness... Is there documentation on which wires to splice/connect?
Also, in regards to coding LCM... Does it matter which software I use depending on if I source an LCM IIIb or an LCM IV?
Then, they have these:
But I don't want to spend 50 bucks on 2 adapters, if I already have the pigtails, and just need to wire them up.
Thoughts?
Well, I ordered the adapters. They took about 2 months to get to me because they were special order from Germany. I didn't want to do all that soldering laying in my trunk, so I went with the adapters instead. Up to you.
Bumping an old thread...sorry about that...but I’m curious is the ballasts are plug and play with he pre-facelift cars? I’m wanting to put these tails in my 97 540i. I have the lights, the ballasts will only cost me $20 if I go back to the yard. If the ballasts make the winning a plug in affair then I’m going that route and saving the time. If I still have to cut plugs apart and splice wires I’m just going to save my $20.
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