djmarchand

After getting a warning message to check my left low beam headlight on my 2008 C300 (USA model) and seeing that it was out, I turned the headlamp selector switch back and forth, no change. I pulled out the lamp- stock halogen H7 (and there wasn't a wire retainer like on the right, but whatever) and it was good. I checked it with an ohmmeter (ok- low resistance) and with jumpers to the battery (it lit).

After struggling with finding a fuse diagram (in the trunk toolkit of all places!!) I see fuses 28 and 29 labeled headlight range adjustment, 10 amps. I pull both while the right low beam was lit. It stayed lit. No other fuse relates to headlights.

So what is going on here? A previous cryptic post says that there are no fuses, headlamps are computer controlled. What does this mean, is it true and how do you fix it?

David

Doa

check if you have voltage first.
if you don't check fuse F29 or F30 depending (10A fuses) and should be located at the bottom right of the fusebox if you stand in front of your car.
atleast with mine its like that but i've seen fuseboxes with a complete different settup
when i have a fuse blown i always check all of them just in case

djmarchand

The bulb is good, but it doesn't light, ergo no voltage. I pulled fuses 28 and 29 while the right beam was on and it stayed on???? And both fuses were also good.

David

Doa

if i follow my list,
28 should be a 7.5A fuse from the kombiinstrument
29, 30, 31 & 32 are related to the headlights.
but i've noticed some W204 have a complete different fuse setting so i'd check all 10 & 15A fuses

mb techman

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mb techman

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djmarchand

What is the front sam? What you describe is a fuse box aft of the brake fluid reservoir. I assume that it is a combination fuse box and microprocessor control module. My googling tells me everyone, and I mean everyone refers to it as a SAM. I am curious what SAM stands for.

BTW I misstated the numbering of the two 10 amp fuses in this box labeled headlight range adjustment. They are actually 29 and 30.

In any case is this mysterious sam user repairable?

As a 66 YO shade tree mechanic in his teenage years who started with points, plugs, condensers, relays and solenoids and moved on to program microprocessors in machine code, I am shocked that something as simple and critical as headlamps can be waylaid by a microprocessor module. But hey, maybe that is progress ;-).

David

Carsy

There are a few of us around David !!.

Any voltage at the headlight bulb contacts with your multi meter ? .

Take a good look at the contacts on the bulb & bulb holder for damage .Give both a little polish with a piece of fine emery paper. Make sure contact spring is not broken if there is one.

This might help https://mbworld.org/forums/c-class-w...sam-whats.html

keith100

[QUOTE=. I am curious what SAM stands for.


David[/QUOTE]

Signal Acquisition and Actuation Module.

Its not the fusebox, and is nastily expensive!

MB seem to have weird fusing - tons of fuses for this that and the other, but only one for the entire HVAC and none for the headlamps.

Good luck I hope you find a cheap solution

jiggsmurphy

Same problem in a c300 today. I took it to a pep boys to change 4 tires and when i dropped it off, all lights were operational. When i got the car back, they had changed the lights from Automatic (A) to off (o) on the light selector. I turned them back on when i left and of course i get a "check lower right beam." I thought it was a weird coincidence that my bulb goes out the same day of replacing tires, however, my bluetooth phone didn't pair back up. So I drove back to the shop and they told me i needed a new bulb. I had the guy put the new H7 bulb, and it didn't work. Any chance that something was changed or tweaked in the electronics. I know there are pressure sensors in the tires that they may have reset?

Did you ever get this fixed?

lbenard

I see notification to check lower left beam, however light is working, at same time, lighter stopped working as I had phone charger plugged in. since lamp is working, what can I check

campeau

Many people make this same mistake of working on the wrong light. Hi-beams are upper and closer to the center of the car, while the low-beams are lower and further out. My low-beams have a clip, my hi-beams don't.

Rossafuss

Any update on this from anyone? I've got a W211 with the same problem. Low beam left is out, right low beam works fine. Bulb is good.

Tiffany Dunkle

I am having the same issues. I took my car to shop and they charged me 527.00 to replace the front two low been bulbs and for doing diagnostic which they couldn't figure out what was wrong. My lights were flickering off and on and so they said alternator needed replaced. I am in over $2200 in repair bills and still my lights are malfunctioning. I also changed my blinker bulbs a week ago and it is out again. Any advice would be nice. I have a print out of all the codes.

Aaron G

I'm experiencing the same problem on my C300. My Bluetooth isn't connecting and my right low beam warning message has popped up. Have you had a solution for this problem by any chance?

Aaron G

Has anybody found a solution for this issue?

Jimmy Vito

R J

Did the alternator replacement fix your issue?

Dan Carl

I do know how to fix it all together,as a proud owner of a Mercedes Benz myself...sell it and buy a Chevrolet,GMC or even a high end Asian brand