W203 2006 C200 Driver side Headlight and smallest bulb wont turn off

[A2amali]

Hello,
I have C200 2006. Out of the blue the driver side headlights will not turn off.

Only way to run off is to disconnect the battery right now.

I have switched off the timer for courtesy lights and also turned off the day light running from the console.

The switch is working because I can turn on the other headlight and off and turn on the front and back fog lights.

Could someone advice me what I need to change to fix this issue.

Thank you.

 

[Blobcat]

Hello and welcome,

Water in the front SAM is what I'd be looking for

 

[A2amali]

Hello and welcome,

Water in the front SAM is what I'd be looking for

Im sorry what is front SAM? do you have part form W203 2006 please.

 

[Blobcat]

It is a "Signal Acquisition Module" a fancy fuse box that takes signals and sends them to the relevant item to work. They have a tendency to get wet, which leads to corrosion on the circuit boards and random electrical issues ensue

 

[A2amali]

It is a "Signal Acquisition Module" a fancy fuse box that takes signals and sends them to the relevant item to work. They have a tendency to get wet, which leads to corrosion on the circuit boards and random electrical issues ensue

Ah I understand now, actually the same side light has been playing up, like message saying evening bulb not working and even when you change the bulb it sometimes worked and other times it didn't. It was evening light so I ignored it, been going on for few years. So it must be the corrosion.

Is there any video or something on how to change SAM. I have a local garage that can replace it, but it would be good to know how.

Thank you for your help.

 

[A2amali]

I have managed to order the SAM unit that corresponds to my car. Just quick question. Do i need to get it programmed and if so any idea how to do it.

 

[A2amali]

Hello bobcat

I called Mercedes and got part number. Then got one in second hand market.

The part replacement did the job and everything is working perfectly

Thank you

 

[A2amali]

Sorry, just to be clear, no programming was required for the SAM unit if it corresponds to your car.

The part number given to me by Mercedes was not 100% correct because this one keeps telling me that the side lights are not working, but my car dont have the side lights, also the part number on my Part was different but it did work.

So I would suggest, you open the box and read the part number in your car instead of calling Mercedes.

The SAM unit was on the left side near the windshield. There was no corrosion on the circuit board at all, but I am guessing the IC must have fried/glitched after long use.

The reason I HAD to change SAM unit is because my headlights will not switch off killing my battery, however, the driver side evening light just used to switch off and on for few years and also recently for few months the air conditioning will start by itself even when the aircon was off. These were obviously small issues and I just ignored them but the point is that SAM unit must have been failing for awhile.

 

[Rory]

The part number given to me by Mercedes was not 100% correct because this one keeps telling me that the side lights are not working, but my car dont have the side lights, also the part number on my Part was different but it did work.

Maybe you use a different name - perhaps parking lights? The small bulbs in the headlamps - as they get old they can cause the warning even though they still work.

Apparently if you don't use "Mercededes" bulbs this can happen even with new bulbs although I've changed mine and used some random make and it stopped the warning.

Could be it's referring to side marker lights (like they have on US cars) - in that case ignore me!

 

[A2amali]

Maybe you use a different name - perhaps parking lights? The small bulbs in the headlamps - as they get old they can cause the warning even though they still work.

Apparently if you don't use "Mercededes" bulbs this can happen even with new bulbs although I've changed mine and used some random make and it stopped the warning.

Could be it's referring to side marker lights (like they have on US cars) - in that case ignore me!

Hello Rory,
Yes exactly. The message is "Side Marker lights". I thought that its for the model with side marker lights.

But from your message it sounds to me that its just programmed like that so if i need to i could ask them to turn of this warning? I do have a service due in a month when they will need to use the computer to rest the service interval, do you think they could turn off these messages? Its not a big issue, just be nice to not have errors

 

[Rory]

I've seen it suggested that new SAMs need to be programmed to match the car, but also that it might be a one time process, so not sure you can re-program an old one. Someone with StarDiagnose (or simlar) might be able to code out the un-needed functions.

 

[mioba]

So I would suggest, you open the box and read the part number in your car instead of calling Mercedes.

Just to add. It is very unlike merc to give an incorrect pn if they have your VIN.

Futhermore its very unlike merc to give a pn full stop.

Many parts do get superceded so the pn does change.

Glad you are sorted.