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What I unearthed today was a mess which I later found out seems typical MB of years gone by. While troubleshooting a corner marker light on the wif's 2008 C350 I decided to have a look at the running (corner) lights in the headlight assy otherwise known as eyelid and eyebrow lights (little 194 type) and swap them for LEDs I laying around.
No sooner did I remove a perfectly good operating light did I find the wiring insulation crack in pieces upon removal. I swapped in the LED and it failed to work and got the dash warning. I rotated it to make sure the polarity was okay, this time it illuminated for a couple seconds before going dark. I swapped the old blue bulb back in and it also wouldn't work. Upon closer inspection, the insulation wasn't just cracked at the base of the socket it was cracked in 4-5 other location in the cumulative 4" of wiring showing. WTF Mercedes, wiring like this is for British cars!!! If it weren't for the computer controlling the system the wiring is a fire waiting to happen.
TL;DR.....Is there a headlight assembly wiring harness (internal to the housing) that's available for the early W204 so I can replace this mess or is a complete headlight housing replacement necessary? FWIW, I have the bi-xenon headlights so full replacement is not for the faint hearted.
Reviving an old thread because I'm in the same situation.
I was able to locate a replacement headlight wiring harness for the halogen headlights, but nothing for the bi-xenon headlights. Was anyone able to locate one, or come up with a reasonable fix?
Hey Sully, I agree with the revive. I took apart my E500 headlights recently to discover a nightmare of cracked wiring insulation on almost every wire internally. My Morimoto EvoX-R 2.0 projector upgrade went from exciting to one hell of a time- consuming task. For reference, I have the active Bi-xenon option adding several additional wires and motors to the mix. Already depinned several connectors so I can solder and heatshrink new wires in. Going with silicone insulated 20awg and 14awg wire accordingly. Will update all on the matter soon.
Last edited by ChromeSmoke; Feb 7, 2022 at 06:43 PM.
I ordered some silicone insulated 20awg wire, but that seemed way thinner than the wire that's currently in the headlight. This drove me to ordering some milspec 10 and 12awg wire. milspecwiring sells by the foot, so I didn't have to purchase an entire roll. Shipping is a bit of a nightmare where I'm located so all these changes results in delays. I will keep the post updated when I get the retrofit done.
Well I just ran into this myself. I too am upgrade to an EvoX-R in hopes of brighter lights. I needed to do the lenses anyways. My current projectors are a bit cloudy so was hoping of the best. At this point a bit angered. Any other tips you have? I am not sure if one can just buy the interior here, even on eBay?
Originally Posted by ChromeSmoke
Hey Sully, I agree with the revive. I took apart my E500 headlights recently to discover a nightmare of cracked wiring insulation on almost every wire internally. My Morimoto EvoX-R 2.0 projector upgrade went from exciting to one hell of a time- consuming task. For reference, I have the active Bi-xenon option adding several additional wires and motors to the mix. Already depinned several connectors so I can solder and heatshrink new wires in. Going with silicone insulated 20awg and 14awg wire accordingly. Will update all on the matter soon.
This seems to be common among a few models. 1) Do the replacement Hellas that are new suffer the same issue, or did they change the internal wiring at all? and 2) does Depo make an AFS light?
I was checking out some of the other woes. I do have mine shrink wrapped but it was a pita. Some of the other wires appear to be failing now too. Suffering intermittent issues not sure if it is worth the effort. Pricey lights though.
I have also unearthed the same thing in my w204 c300. My wiring inside the housing is bare and several of the bulb sockets are warped or cracked. I am in the process of researching aftermarket headlight assemblies as we speak. This kind of let me down as this car is a 1 owner with 131k miles and great maintenance records. Must have been a bad design.
It was a pain, but glad the new projectors are in. The AFS lights do not work as intended, I'd rather disable that feature if I can ever get my hands on STAR. Best of luck, It is tedious at best, and expensive at worse. I am not quite sure why the insulation was so poor inside the headlight. I love the car too much to give up on it for that.
I know this is in the W204 section but I finally got around to replacing the wiring in the passenger headlight of wifey’s 05 W203 C230 this last week. Had ordered a non-OEM headlight harness on eBay a short while back when the bright went out due to the cracked insulation.
Was able to remove the headlight assembly with only partially removing bumper, then carefully disassembled headlight which included several clips for the lens, several torx screw for the inner plastics, and several ball & socket type fitting for the adjusters.
After disassembly, replacing the wiring was relatively simple - be sure to tuck wiring in the small slots that are meant to hold it away from the parts that get hot. Also make sure to test before putting all the way back together. The job seemed intimidating but was not bad overall, especially having removed the headlights before. Shouldn’t take longer than 1.5 to 2 hours. Hope this helps somebody out there.
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