Your ballast resistor may be gone.

 

Thanks Skylaw , i forgot to mention this is a normal halogen bulb , non hid could it still be the case?

 

look at the wires

I noticed that the insulation was deteriorating on the 3 wires to the bulb

 

Mine did exactly the same thing. One day the bulb was dead, I replaced it, still no go.

These cars use what is called an "electronic fuse" in the workshop manual, which is a SAM (Signal Acquisition Module)

There is one SAM for each side of the car and it controls (among other things) the exterior lighting. They are REVERSED for headlights, so although the R side SAM controls all of the right lights, it controls the LEFT side headlamp. I believe this is for safety reasons (so one entire side of the car doesn't go dark if it fails)

I checked mine with SDS and it came back with an error. So I replace it with a used one. 6 months later, the headlight is now starting to pop up with "check left headlamp" errors once in a while and the headlight goes off for a few seconds and then comes back on. So my SAM has failed and I need to buy a new one (not buying a used part again......)

Have it checked, but you most likely need to replace the SAM. It's in the fuse box under the hood, and very easy to access. The new one even has a diagram on it that shows how to remove/install it.... it just unplugs and snaps out.

Used SAM was $100 but I think new they are $200ish online.

 

Thank you bhatt I will look into this , do you happen to have the part number for the left sam?

 

I looked mine up at epc.startekinfo.com -- you need a credit card to register but there is no fee. Have used it for years and not paid a thing.

You can look up the exact SAM part number for you car by VIN number. Note that when it says "replaced by yyyyyyyy" for part number xxxxxxx, it means you can use either xxxxx (which your car came with) or yyyyyyy (which is the newer part). Either will work.

Find your part # and buy it online or on eBay.

I think (but can't remember for sure) that for some models, the SAM is the same part # for both sides. For others it is different. Make sure if yours are different that you are buying the right one!

It's a 10 min job to replace. Pull the fusebox out and the SAM is right under it. It's the metal thin box attached to the bottom.

Look on ebay for W220 Fusebox and you'll see what I mean. The black part with the fuses is the fusebox, and the silver module below it is actually the SAM. Most sellers think it's part of the fusebox and sell it as such, but it's actually 2 separate pieces.

Pull the fusebox/SAM, look on the side of the SAM at the diagram, and swap your old one with the new one. No need to code the new one to your car or anything.. it will just start working.

 

interesting...because everynow and then, I get the warning for various lights, but after being parked, the errors go away, does this mean an issue with the SAMs?

 

Hello everyone, this forum has a lot of good information, thanks for it. I have the same problem with my drivers side low beam. I checked to the plug to see if I had power and had no power there. I want to replace the SAM but didn't find it. Is the SAM located under the fuse box or is it the two metal boxes on the side. HELP

 

I forgot. I have a 2002 S430. Also I believe the two metal boxes on the side are computers but not really sure

 

Some comments:
- It gets really expensive really quickly when you try to solve a problem on a car as complex as the W220 by throwing parts at it, hoping that one of them will fix it. Research and diagnosis are usually much cheaper.
- If I remember correctly, the left low beam headlight is powered thru the right SAM.
- The lights (along with many other things) on the W220 are not powered thru normal fuses. Instead, one of the many small computers on the car monitor the circuit, and if the computer senses a fault, it simply cuts off the power. You may need to find and fix the problem before the computer will turn the power back on.
- You may have normal incandescent bulbs, or HID bulbs. Failure modes are different. Incandescents can be checked with an Ohmmeter, as can the ground/earth connection. HID bulbs have extra "black boxes" (ignightors) that can fail. Sometimes, the easiest way to test is to swap parts from side to side.

 

Just had an issue with one of the ignitor adaptor cables, though this was with an aftermarket bi-xenon retrofit. Turned out the ballast was fine, the bulb was fine, but the AMP-to-D2S adaptor had a bad (cold) solder joint from the factory. I noticed this after popping open the plastic case surrounding the D2S receptacle. Just re-soldered the wire back onto the contact, and all was fine. Took maybe 5 minutes.

In jdfking's case, I can think of four possibilities: the bulb, the ballast (including ignitor), the right SAM, or the internal wiring in the headlight housing. M-B/Bosch used some sort of supposedly eco-friendly wire insulation that tends to dry-rot and crumble at about the age our cars are now. Such was the case on the 2000 S500 project car, the 2003 S430, the 2003 S600 TT, and the 2005 E320 CDI. This exposes the bare copper wire, and you can actually get short circuits inside the housing this way, a rather dangerous condition in my view. Give me the traditional rubber/plastic wiring insulation that lasts 50+ years, any day.

Another possibility is that the headlight cable isn't plugged in all the way, though that seems to be more a problem on the passenger's side due to the shorter length of the wiring harness.

And finally, this odd thing happened when I was reinstalling the refurb'd headlight in the project S500. This was right after repairing the aforementioned messed up ignitor cable for the right-hand assembly. The left side low-beam came on just fine. Not so the right side. Tested the low beam outside of the car (applied +12V power to the yellow wire's terminal and ground to the brown one with a spare car battery), and it came up great. However, for some reason, the low beam wouldn't come on at all when installed in the car. The high beam was just fine. So, I stuck a voltmeter on the wiring harness's plug and turned on the low beams. I saw a momentary peak of +12v, dropping down to 8.35V. That 8.35V would last maybe 10 seconds, and then I'd see another spike to 12V. So, this looked promising; apparently the SAM's now re-trying to see if it's got a proper load. Plugged the headlight assembly back in, and it came right up.

 

I had the same problem. didn't understand things.. couldn't get rid of the check Lamp error. no matter what I did.
after spending around 4 hours in the bitter cold checking fuses and connections and so on. I gave up.
came inside in the warmth had a long cup of coffee Latte.
Went out again to give another try.. only to realise my own stupidity.. I have been changing the wrong lamp on the right side. been changing the bulb in dipped light compartment.
-Just double checking would save a lot of time.

 

Ha! Happens, man. There are two types of automotive DIY-maintainers:

1.) those who have overlooked something stupid, and
2.) those who will.

Welcome to the first club; good to have you as a fellow member.