Keyrat

Guys, my entire passenger side headlight is not working. None of the lights on that side work, no turn signal, low beam, high beam, etc... I've check the list of fuses and I don't see which one could be out to cause this. Does anyone know what could be the cause of this problem? Thanks

Vader55

Pull up the hood and check the two wire harness's that plug into the back of the headlamp ( there is one large/wide and one small one) The larger one being un-plugged could be the culprit. There is a fuse chart posted on benzworld.

Keyrat

You are exactly correct, the larger plug was slightly unplugged. Thanks for the fix Vader55! Now I can see where I'm going!!!!

Ring A Ding

Friends:
I am in the same spot, hence this nudge to the top of this old post:

1. W220 S430, yr. 2000.
2. My lowbeam driver's side is out, but the bulb is fine (as is the replacement bulb that I installed). So, I presume a fuse issue. The fuse chart does not specify a fuse number.
3. Prior posts instruct: that the fuse for the head lights of the W220 is controlled by the "SAM Unit".
4. Forgive my ignorance, but what is the "SAM Unit"?

Any guidance is appreciated.
Ring A Ding

Skylaw

In addition to what has been suggested, it could also be a bad ballast resistor.

SAM is "Signal Acquisition Module." It functions as kind of a router, accepting signals from various controls and sensors, and routing the signals to the proper location to cause an action. A W220 has three of them - one under each front seat and one under the back seat.

The SAM unit does not "control" a fuse; but it would control the signals to operate a device on a fused circuit.

instinct

Hey. I don't see an answer to your question. I ran into the same problem. I have replaced the high beam H7 - 55w bulb with a 100% identical one and it no longer turnes on. I have tested on the right side and i screwed it up there too. Now I have no high beam at all on both sides. I have tried to search online but found no answer to this. My low beam works 100% and all the other bulbs in the headlight except the high beam. Is that a fuse and if it is where would I find it? Thank much

Skylaw

Ring a Ding's question was answered, as far as we know; he gave us no further feedback.

Regarding yours, if I were tinkering with my car and getting more failures than I started with, I'd realize I don't know what I am doing and take it to my dealer.

Ring A Ding

Somewhat consistent with Skylaw's advice, I punted and ended up going to my independent mechanic. He reported it was a fuse issue. For the 2000 S Class, the fuse is located under the rear seat, passenger side. I must have pulled the wrong one when I changed the fuses (if I recall, it is difficult to track the numbering of the fuses).
RingADing

Urquizo

Skylaw- I am having the same right headlight not working after bulb replacement. I think you are on to my problem. You mentioned three "ballast resistors" I looked under the front seat and rear seat. I can't locate the ballast resistors. If possible can you sent me or post a picture of the ballast resistor and exact location? Of the three ballast resistors, which ballast resistor controls the front passenger headlight?

Urquizo

Skylaw- I am having the same right headlight not working after bulb replacement. I think you are on to my problem. You mentioned three "ballast resistors" I looked under the front seat and rear seat. I can't locate the ballast resistors. If possible can you sent me or post a picture of the ballast resistor and exact location? Of the three ballast resistors, which ballast resistor controls the front passenger headlight?

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Skylaw

Not three ballast resistors; there is only one on each headlight. There are three SAMS, associated with each fuse box in the engine compartment and under the rear seat. The passenger headlight (on left hand drive cars) is controlled by the right SAM.I have written the rest of the information you seek on the W220 forum on BenzWorld; I am sorry, but do not have time at the moment to look it up. Check the W220 S-Class Encyclopedia sticky there.

Urquizo

Skylaw, I removed the entire right headlight assembly and I noticed my 2004 S430 headlight does no have a ballast. Maybe only the older first generation w220 come with ballast resistor. I wonder what else could be causing my dead headlight.

wallyp

The W220 may have HID headlights, which have an igniter unit to fire off the lamp, or it may have standard bulbs, which have no igniters or resistors. It appears that you might have standard headlight bulbs.

If the headlamp does not burn, the usual list of possibilities include:
- The bulb has failed.
- The bulb is not installed properly.
- The bulb is not getting power. There is no "fuse" as such in the headlight circuit. The SAM (Signal Acquisition Module) on the opposite side monitors current flow to the low beam, and cuts off the power if the draw is greater than specified.
- The bulb ground connection is faulty.
- The bulb connector is not fully inserted. This should be the first suspicion of all of the lights in that headlamp housing have failed.
- The SAM or a connection has failed. This should be the very last possibility that you consider. Throwing parts at the problem hoping that something good happens is very expensive.

No magic answer - you are the only one who can test each of the possibilities and find the problem.

Skylaw

Thanks for putting it together succinctly, wallyp. Things have been extraordinarily busy for me lately, and will likely remain so for some months to come, and I had about 30 seconds to respond to this yesterday - though the information was available in the references I was able to provide (all too briefly).