Mercedes SAM Bypass for Headlight Not Working

In this video, I show and describe how you could potentially get your headlight working due to a bad front SAM module. I show by performing tests that the electrical system is still safe even when installing bypass. Be cautious and perform any work at your own risk.

[@jajcozucchini5438]

very good educational video . Ive done it on my 08 C350 and it works perfect . Dealer wanted. $ 1620,00 for this repair . It only cost me $ 58.19 total . Thanks a million for detail instruction . It made a big difference

[@DTEAuto]

That's great to hear! I'm glad you got it figured out and working, thanks for watching!

[@MO-cc7ob]

2024 and sill works! - I just did on my W212 and worked like magic! Dealership wanted 1600$ for new SAM lol thank you 🙏🏼

[@DTEAuto]

awesome! 👍

[@dbinca7511]

Hi, for you and anyone else out there... Firstly, I was thinking to do the same thing but had concerns how the SAM would handle it, and error messages. So you testing video was most useful to confirm the solution and show power was less than 5 amps etc... I used a Rely and a 5Amp Fuse for the feed. My car is a 2008 E350 Sport and the drivers headlight was not working. After opening the headlight unit to repair the Mercedes ECO crap wires (Who didn't test that useless wire before using it in manufacturing!! Mercedes goes to great lengths to make everything CANBUS with test circuits everywhere - hence the headlight SHORT CIRCUIT, diagnosed the error but also didn't report it smoked the SAM internal switch for the headlight! Anyway I digress...). When testing with a meter I saw Power for a brief moment then SAM turned it OFF. So I calculated that the wire was not shorted. Hooked the power to the wire at the headlight... ran right Low Beam signal wire around the back via the Cabin Filter and to the SAM Area where I installed the Relay and got Power from PIN 30 0n the empty Relay M assigned to "M - SEQ pump control relay" which is not present on my car. Secured Relay to Earth Post just in front of the SAM and took the Relay Power to wire at Headlight and spliced into LOW Beam Yel/Blk wire right there - Work Great... and I got lucky as the Power monitor for LOW Beam appears for now to be happy it can see power and I don't get a dash warning. A win! I also didn't know about the BAD Wire in the headlight unit until this problem, and I did see after I dismantled mine that several have done the same - yes it is possible to open up the unit with patience, rewire with care, I soldered new wire to the stubs... I slid some long lengths of heat shrink on the indication and I couldn't be hassled to remove that to get to the back of the fitting. Just take your time and it's not a difficult job. So my 2008 W211 E350 no has both headlights working. Thanks for taking the time to do your video, I am sure there are many without unlimited funds that might benefit from knowing its OKAY to do this without causing further harm to SAM or anything. Hope everyone has good results as I did... gabled, worked, but a winner. Thanks again. Dave.

[@djosbun]

The idea to tap into the other headlight and verifying the amp draw was OK was genius, Sadel. It allows your customer to continue driving the car until another module becomes available on the used market. Super job! I was driving with Lucas to Jungle Jim's during part of this video. When you said "checked to make sure this was kosher" he turned to me and said "he talks just like you do, dad". I was all smiles!!

[@DTEAuto]

Thats definitely funny too hear, but glad the east coast in us can relate lol, thank you for watching and have a good holiday!

[@mrduncan2784]

Nicely done. Simple and good solution. I appreciate all of the testing you did to make sure the system would work properly, safely and reliably.

[@LkOutMtnMan]

To fix the left rear tail light/stop I replaced the lamps with LED and wired the stop and tail circuits to the right side.

[@luismanuelvelazquez9602]

I m having the same issue with my 2009 C350 driver’s side Found this video. Very interesting I will do it cause my mechanic shop that specializes on mbz is charming me $1100 for changing the module

[@dougsautoservice7203]

Awesome bypass, and great to see you took the time to do testing! thanks for sharing 👌

[@EnriqueHernandez-qt9pp]

I'm having the same issue but with the 08 e350, just replace the headlight assembly and no low beam so the signal is missing, I just couldn't get the right wiring diagram to track the wires

[@user-tn2lm5rz1p]

Thank you for the video. The left side headlight on my 2008 CLS550 does not work. No low beam , high beam, turn signal or parking lamp. I have the same issue with the insulation coming off the wires in the headlight assembly. as your car. Is there a quick and simple test to check the SAM unit vs the SAM unit needing to be reset?

[@DTEAuto]

check if it's sending out power supply to turn on the lights, if not and it's not a wiring problem, then possible the SAM is faulty

[@JoelAutomotiveInaction]

Great diag and explanation of though process 👏

[@desiretejondon9268]

understandable explanation, however it is a temporary measure to help out, in order to replace the SAM. it’s also educational, thank you

[@bobczz3919]

I have a 2009 mercedes C300. The glass was cracked on the right headlight but it still worked. I bought a new headlight assembly and removed the light and disconnected the connector to the assembly. I got the new light assembly and plugged it in and nothing came on. I then connected the old light which was working and now it wouldn't turn on. I was completely baffled. I then thought maybe it got its ground from one of the three mounts. I made a jumper to a good ground and hooked it up to all three mounting locations and still nothing happened. I am at a total loss. If you could please shed any light on my problem I would be so grateful. Thanks, love your videos.

[@DTEAuto]

halogen or xenon ?

[@bobczz3919]

@@DTEAuto Thanks for replying, Halogen. But, I figured it out, I had to disconnect the battery and reconnect it. Then it worked. Thank you so much for your videos.

[@scottschantz2553]

Great improvisation Sadel.

[@runningbamboo9980]

I think it must be current sensor (a small resistor) open circuit.

[@MoroccoSoccer]

Thank you for your explanation , this is really helpful, I have the same problem

[@GrumpyOP]

What do you suggest for it being just my driver side low lamp doesn’t work ? I’ve tried replacing bulb doesn’t work, I had someone tell me they think it’s the module

[@DTEAuto]

I would attempt the bypass I showed here, use the good side to provide power to the dead side

[@michellopes9750]

I'm getting 3.4v on the yellow wire (Right low beam). How to fix it?

[@Juanc.Chavez-qm4ur]

Es lo que yo aria si me lo aprueban, el problema sería que el código de falla de la luz izquierda no se borra ya que el módulo no lo reemplazas , saludos desde la Florida gracias por compartir tus conocimientos

[@paul44742]

Sheer Brilliance! Thank you for this video. I too am faced with this problem only in reverse, in that the passenger side is not working. Certainly this can be done in the other direction but my question is if there is a certain size relay or manufacturer of the relay that you used to do this? I hope that this message reaches you, I know that this has been on here for a little while. Thanks again for the details. I will be doing this to a 2009 C300.

[@ronfussell8244]

I have a 2001 s430 with the driver side out,I'm not the electrician by no means,interested in doing this,just not sure where to take power from and the relay prongs,I'm impressed.

[@DTEAuto]

you would have to tap into the power feed to the good working headlight bulb

[@rjfussell]

@@DTEAuto OK,so that works as the trigger,12v to relay,one to input to headlight not working,and the one to ground.

[@kritsonisklan7712]

Can you post that excellent detailed wire diagram

[@TheStevePow]

Very helpful and thorough, thank you 😊

[@DTEAuto]

Glad it was helpful!

[@r.weaver3769]

I wonder if tracing the circuit in the SAM, and find the failed component, probably the power driver chip, IC, or capacitor, might be a feasible repair, since so many modules are being discontinued. There are shops that repair these items as well. Just thinking out loud.

[@DTEAuto]

Yes that is definitely something to consider as on option for sure.

[@worldfitnesstrainerradekve9234]

I thought of that too with bmw X 3 there were xenon headlamps so many wires but I decided rewire all headlight and it worked, 2 y later the other headlight died . Now it’s happening on my ML350 mercedes. It’s about the 15y when the wires starts to bridle and touching each other. But here you saying customer bought second headlight still didn’t work 🤷🏻‍♂️ it’s a lot of work to rewire xenon headlight it was over 15h have to heat the headlight and unglue the glass from the plastic than fix and glue back together.

[@markthomas3858]

Thank you for your video,my problem is the drivers right side head lamp low beam and the back right side brake lamp is showing a fault..I think I need two relays :)

[@reamer59]

Well explained, it was very helpful, thanks.

[@georgec7798]

Too bad you couldn't crack open that Sam, you could have replaced a $2 IC chip and got it working again. I replaced three on mine because I jump started my car and it must have sent too much voltage to the Sam IC chip.

[@DTEAuto]

thanks for the info I'll keep that in mind for the next one

[@markmanning6773]

Do you have the part number for the ic chip? Would you happen to have a link to replacing the ic chip? Thanks

[@georgec7798]

@markmanning6773 Hi, I didn't take a picture of the IC and I didn't make a video because it took me about eight hours to replace a few of them. The casing is kind of difficult to open so be careful not to damaged the board. If you can get it open you need to look on the top of every IC chip and look for a burn hole it will be very obvious especially with the magnifying glass or an eyepiece. You also need to look for white on the board because white indicates water. You can try to clean it with a toothbrush and alcohol. If you recently jumped your car with a car starter, another car or jumper pack then the IC is most likely the problem. If you know how to use a digital meter you can also check the simpler things like diodes and resistors. I can't tell you this, the IC chips that need to be replaced are the thinner IC chips not the wide ones. Please keep in mind that this info is only for the Mercedes C230 w203 chassis rear trunk Sam / fuse box.

[@markmanning6773]

@@georgec7798 thank you so much

[@georgec7798]

Not sure if my last message went through or not. As I was looking for parts to repair a refrigerator board I found the IC chips that go in the Sam / fuse box for the 2004 Mercedes C230 w203. Please keep in mind that these are SMD not through hole. Try to get them at a reputable place like Mouser or digi-key not Amazon because they may be crap. Here is the model number of the IC. ULN2003A

[@SafetHalilovic-fc9du]

Kako rjesiti problem sa farovima neradi.hvala

[@andrewalves92]

I have both that have gone off 😔 what can i do...both my dipped lights are gone...and i can't seem to see the problem..the driver side went then the passenger side went later on what can it be ??

[@DTEAuto]

possible bad module

[@chrisparma3440]

could u please share the relay information relay number and mayby where to purchase. tks

[@jcarlos115]

Would the wiring be the same for a 2010 C class! Thanks for the advice

[@DTEAuto]

It could be similar but more importantly is that is has to be for halogen bulb setup like this one was, not the xenon

[@clivemckinleyNewstarkaraoke]

Thanks for this video seems I'm having the same problem

[@xlyamx]

i have a 2010 glk350 4matic. i have a code in the SAM for a short/open circuit in the left fog light. i was installing LED bulbs and i put the left on in the wrong negatiive/positive ports and when i turned them on.. the left one didnt work. how can i fix this problem? do i have to buy a new SAM/fusebox? or is there another way?

[@DTEAuto]

I would venture to say that if anything it might be possible to do a set up like how I did for the headlights on this video, use one side to power up the other. This is of course if the driver internally is not working in the SAM, wires and output would have to be checked

[@johnwalters7646]

Could I do a similar fix on a vito xenon headlight? Voltage is higher and there are ballast resistors I think 🤔

[@DTEAuto]

I don't think this would work on xenon setup

[@markpasieka]

RESET THE Computer... I had a buddy stop by with the same biodegradable German bullshit wiring... Insulation flaking off... Some electrical tape.. Used my MBII Carsoft computer in regular OBD2 ...saw no relevant codes...but erased them and now the headlamps work

[@Casmige]

The SAM detects an expected “resistance” when actuating the lights or any circuit actually. If the SAM doesn’t detect an expected resistance in the circuit?, it completely shuts off power to that circuit & you’ll have to go in & clear the fault code before testing for Power. NOT simply bypass it…smh

[@markpasieka]

Thank youuuuuuu!!! Exactly !!!

[@pauliroha5506]

Hi, I really like your diagnostic methodology. I have a 2011 R350 with an LED fog lights that will not turn on. I have measured the voltage on the connectors when they are turned on and got 0 volt. There is also a message of blown or open circuits on the fog lights. However, when I connected a direct 12v to the fog lights, they worked very fine. I have looked up the wiring diagram, but I am a bit not sure if it's applicable to my model as what I saw showed like the wiring of 2006-2010 models, though the wire colors are similar. Could you explain how I can go about fixing this or perhaps help me with the wiring diagram of a 2011 R350 with an LED foglights. Thanks so much.

[@DTEAuto]

Looks like the front SAM control unit will be responsible for the actuation of the fog lights. I would start by checking the live data in the sam , make sure nothing is missing. Also, it looks like, they both share the same ground, so I would definitely look into this, since both are not working. Both get turned on via separate lines out the sam, it would be odd if both drivers would be inop at the same time internally

[@pauliroha5506]

@@DTEAuto thanks for the suggestion. I have checked the ground and it seems fine.

[@owlclaw]

the SAM has a current detect feature on each light (all lights) and the LEDs draw less current; this is how it knows if a bulb is blown. If you have someone watch when you first turn on the vehicle, they will flash, shut off, and then stay off with error on dash. You need "Can buss decoders" or power resistors to make the circuit draw the correct current.

[@michaelrussell778]

where can I get diagrams like this for my w221 s550 thanks 40amp fuse keep blowing on the pre distribution fuse box car won't start but can be jumped offby passing this box new battery installed

[@DTEAuto]

I believe for DIY people , Alldata has a limited version subscription you can purchase and get service information including wiring diagrams. Search Alldata DIY, hope this helps.

[@stevepark5504]

Any chance that the SAM has locked out the low beam and would restore with a hard reset? If it has current sensing, it should not allow a short to damage it. Or maybe a rodent or corrosion has damaged the wire under the module?

[@DTEAuto]

I did wonder something similar, and I had gone in with the scanner and attempted to clear and reset and activate, most of the time what I have noticed that if it was not operating due to a "lock out" or similar situation, the module will still be able to work and operate the light with a hard manual command via tester in order to display ability to operate physically just not operating with switch command because something is not reset proper or coded correctly. but to no avail my situation did not clear up or operate with command from scanner. Leading me to believe more of a hardware failure issue. Thank you for watching

[@markpasieka]

Dude...i reset the error codes which only showed O2 sensor faults and the shit works.... Reset with an MBII Carsoft in regular ob2 and pray you have the same luck as I did... No voltage to bulb before the reset....

[@anthonyikechi8456]

I'm asking of compressor reley for c300mercedes

[@davorinkutnjak7260]

Hay, thanks for video. Q: does it work the same on xenon headlight(w204)? Thanks

[@DTEAuto]

unfortunately, I don't think that it will.

[@marcusalvarez3678]

What if both headlights don’t work

[@radutanasie5852]

Hello,i have a W204 C220 CDI from 2007.It has been standing for over 3 mounths,when i started drivein again,turn signal,horn,window wippers and AC not working anymore.Suddenly,AC started working again and also turn signal,horn an window wippers started working all togheter.Do you have any ideea what could be?

[@jasongeorge8523]

SAM module

[@DTEAuto]

I would venture to say that the SAM module seems to be dropping out. Would just have to make sure it's not a wiring problem to the SAM before replacing it.

[@samuelilos2125]

Wipers, Horn, high beam, turn signals not working in c300 2009 model Why?

[@DTEAuto]

possible bad front sam

[@davidessien5465]

Nice video

[@DTEAuto]

Thank you!

[@papecheikhdiop8032]

Great 👍 thanks a lot

[@DavidGutierrez-zi4dy]

thanks.

[@aymenmohamed1134]

👍👍👍

[@Dd-uu4vo]

My goes on and off :/

[@avzpt]

did you ever fix it?

[@westside5753]

It's the fuse

[@Kajmechanic]

Only mercedes will get the most standard of things wrong, all built very bad.