My right Xenon was defective last year and the issue was fixed after the dealer changed the control unit. The symtpon was it would went dead intermittenly in the beginning and it went completed dead after 2-3 weeks.

This morning I noticed that my left Xenon was flicking. After 30 minute commute to work, it was still flickering when I arrived at work. Also, I noticed that the right Xenon (newer) is white while the left Xenon is a bit blue.

The current sympton is different because of the flickering. What can this be? Bulb, ignitor, contorl unit? The light flickers even when the car is parked.

Xenon bulbs do change color as they age, and also if the ballast are bad. This sounds like a bad ballast (i.e. HID control unit). It's not too hard to replace, but it's easiest with the headlight removed, which requires removing (or at least dropping) the bumper. You'll need the OEM part and not an aftermarket ballast because this also has the controls for curve illumination and height adjustment (if your car has those features).

OK. Ballast is the control unit. Thanks. I rememer when they changed the right side, they had to drop the bumper.

I do prefer OE parts. Locally, this part costs $958 CAN. I called an US dealership, they quoted me $736 US. Parts.com's price is $513.

I may not have a choice but to get it locally.

If the ballast went bad, should it throw a code? So far, there is no malfunction.

I noticed the bulb was blue-ish months ago.

No, it doesn't throw a code. When the system is set to Xenon=present, it basically ignores all headlight bulb errors.

I did have a code this morning on the left low beam.

Went to my indie and he said the socket to hold the bulb is defective. This is why the bulb is flickering. Is this the ignitor?
When I called MB, they told me this part is $250, part of the wiring harness.

Interesting. You can set Xenon=present on a halogen system, then unplug the headlights and get no errors. I assumed that meant it just ignored them, so maybe the error is a function of the HID control unit and not the SAM.

I am confused. Ballast and control unit are the same item, just different names. How about SAM?

Your high beams are on all the time on that unit. It has little shutters on the reflector housing that flick in/out to give you high/low beams. If you have active lighting (you didn't say), then there's also shutters for left/right for steering, as well as fog light controls while turning. Using WIS you can exercise them without the lights on - it's quite a show.

Xenons always need to be replaced in pairs - otherwise you'll always get two different colors. They rarely have to be replaced, lasting years.

It could be aftermarket parts, connectors, the controllers, lens assemblies, wiring, data link, whatever depending on who did what in there. Computerized lighting systems like this (and other cars) are not tolerant to trifling around. My only advice is to either replace the entire system with aftermarket or take it to the dealer. I've seen dozens of mangled attempts in the shop to hack these - and none that have been successful. They always begrudgingly pay us to get it back to spec, with the usual shouts of law suits etc coming from the front office lol.

So take it on over there, maybe you're liable to be pleasantly surprised that it's only a minor issue.

Good luck

As I said last time, I was told that the socket which holds the bulb is part of wire harness and this parts alone is $250 CAN.

My question is what is the other end of this socket? Does the wire connect to the ballast? Is this a DIY, do I have to drop the bumper to replace this wire?

there is the igniter on the end of the socket... assuming you are talking about the red plug that you twist on the bulb... the igniter is on the inside of the housing which makes it impossible to replace without opening the housing. In the wiki section there is a different way to replace this unit without opening up the headlight.

I had the same problem as you, but decided to get the igniter, open up the headlight and replace it like you cannot see it was done. My headlights work perfectly now.

and no, the igniter is different from the ballast, the ballast is the aluminium unit on the outside (bottom) of the headlight where the igniter is INSIDE the housing. the ballast does connect directly to the igniter.

Went to dealership. Replaced bulb and the wire harness. The whole bill was $670 CAN.

Money well spent. Now you've got a CLK running with factory specs with one of the most intelligent lighting systems of any prod car on the planet, even as of today.

Congrats -

I recall when I first bought the car, I was really impressed with the lighting system.
I really need a knowledgeable indie locally in Toronto. Any suggestions?

If you are willing to leave your car or sit tight drinking coffee/tea and watching TV, I think we can handle it. One disadvantage is you would have to coop with my assistant offering you snacks and drinks every once in a while

Igor.

There ya go