JimPap

My 2008 C300 has been at the dealer's shop with a dead low beam BiXenon for a week. They keep ordering parts and have said something about software not taking but its mostly over my head.

From what I gather, the BiXenon burner (bulb), is triggered by an ignitor (starter capacitor) which requires a headlight assembly replacement (I guess its built in to the housing). Headlight leveling was also mentioned along with software updating that's not taking.

If I had known that the Bi Xenons had the potential to be this much trouble, I wouldn't have gotten the P2 package. Although this is under warranty, I hate to think about it happening again after it goes out of warranty.

In any event, can someone point me in the direction of how the system works on a 2008 C300?

vic viper

If the lamp unit is ok then there isnt much else that can be faulty than the Xenon ballast, this is basiclly the unit converting 12V into ~30.000V.

You do not have to buy a complete headlight assembly to replace this, the units have part number A2048203285 and A2048203385 if you have curve lights or ILS

JimPap

Thanks for replying Vic,

So what are they talking about regarding not being able to do a software update to register the part?

I'm wondering if they're stalling to fix something else that they've broken.

vic viper

We havnt had any 204 with faulty lights yet, but if something was wrong they should be able to see this by just performing a "short test" with Star.

The control units are the same left or right so it should be a simple thing to switch the two units to see if the error follows..

JimPap

Are the control units and the ignitors the same thing?

I smell something else is up. Maybe I should take a close look for body damage.

They also commented that this is the first one of these they've had.

I'm pretty good at figuring things out. I'd really like to be there trying to help, but I think I'd just tick them off.

vic viper

Older cars like the W211 have two different control units for this, but the W204 and some other newer mercs have the ignition module integrated in the base of the lamp (D1S)

JimPap

They did replace the D1S ignitor and that didn't make any difference. They even swapped ignitors left to right and the same side still stayed dim.

So is the control unit basically a relay that the bulb (ignitor) is built onto? The transformer and capacitors are somewhere else.

vic viper

I do not know what part does what, but here.s a pic of a D1S bulb and as you can see there is a control unit attached to the base:
http://www.xenlight.com/var/132/22929-d1s%20bulb.jpg

Here is a screen from EPC showing the light assembly, position 20 is the control unit attached under the assembly:
http://web.telia.com/~u43305336/scrn89.jpg

JimPap

That second link doesn't look right. Is that for the bi xenon? Reason for my asking is that the ignitor doesn't have that silver black box attached to it as show in the jpg of the D1S bulb. This looks like another model where the silver box (item 20) is much larger and is probably attached via cables.

vic viper

Yes the EPC has wrongfully depictured a D2S bulb instead of a D1, the EPC images unfortunately arnt always as IRL

RLE

Smells to me like they have a version coding problem if they replaced the headlight unit.

I've had Xenons since 2001 in two cars and have not even had a bulb failure. Quit fretting. They'll get it eventually.

moondust

I took a quick look at the circuits for the Bi-Xenons in my 2004 W209. There are 3 modules involved in the control system for each side. Your W204 may be similar.

1. Xenon headlamp supply module
2. Xenon headlamp control module
3. Xenon headlamp ignition module

The WIS states that the Xenon headlamp ignition module and the low beam unit can only be replaced together.

Further, there is automatic headlamp range adjustment via both front and rear axle sensors. Not so simple.

RLE

None of this applies to the 204. And US models do not have range adjustments. Yet.

JimPap

Car's fixed.

I'm half awake and will come back tomorrow and post what they found.

JimPap

O.K., this is what happened.

Short version. Replacement part wouldn't work and got another replacement part that would.

Longer version. The left headlamp leaked water into the control module. They replaced the headlamp but had a coding issue in that it wouldn't version code properly. The part was suppose to be a good sub. (I think that means substitute). Contacted SDS helpdesk for coding issue. Was given a SCN coding string to manually install. Coding string didn't work. Replaced new headlamp unit with old part number without part # sub. Programmed and SCN coded as normal.

I have to say that I can now see why it took a week to get it fixed. A part that should have worked didn't and the work around given to them by the mothership(which I think actually happened twice) also didn't work. I have to give the dealership credit for sticking with it and getting it fixed. And having a 2009 C300 loaner car did take the edge off.

JimPap

You win!!!!

But I have to ask what is all this version coding stuff about?

Is that so that two parts that may look alike but operate differently internally are prevented from being incorrectly matched up?

JimPap

I've noticed for the last couple of weeks that my bixenons don't appear to be aimed high enough to lighten up ahead of the car like it use to. Its both side.

Also noticed that when I turn them on, they don't seem to flip up and down as much as they use to either.

Any ideas?