W204 Electrical Problem

Discussion in 'Electronics' started by Ritchie18, Feb 13, 2019.

  1. Ritchie18

    Ritchie18 New Member

    Messages:
    25
    Joined:
    May 26, 2018
    Location:
    Belfast
    Car:
    Mercedes W204 320CDI
    Hi

    currently have W204, car appears to be blowing front sam unit.

    initial problems were:

    No heated seats, auto lights, wipers or horn not working. Replaced front sam, which worked for a week. And it stopped working again. SAM was matched both part number and software numbers.

    I purchased another front SAM off Ebay -

    Auto mech reprogrammed SAM everything works, however front lights wont turn off, fogs wont turn on - seems theres no power to the light controller.

    Auto mech found water around the rear sam and feels it needs replaced as well. Auto mech feels the rear sam might be causing issues for the front sam. Could this be possible?

    Could a faulty rear sam impact on the front sam?

    Strangely when I disconnect the battery the wipers would work for a short period.

    Many thanks
     
  2. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

    Messages:
    5,990
    Joined:
    Jun 10, 2002
    Location:
    Berkshire, UK
    Car:
    MY04 SL55, MY17 GLC250d AMG Sport
    Heated seats are done by the Rear Sam. If front sam is not coded correctly you can get front lights on and fog lights off .. The light switch changes between being connected by a LIN network to being connected by 5 wires. If its set wrongly then it says "can't see light switch, turn on lights". It is quite possible it also turns them on when it can't see something else it wants ..

    Did he use proper online Xentry Diagnosis and SCN code the front SAM, or was he using another tool. (ask him). Are there any error codes from the front SAM ?

    Cheers
    Richard
     
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  3. OP
    OP
    Ritchie18

    Ritchie18 New Member

    Messages:
    25
    Joined:
    May 26, 2018
    Location:
    Belfast
    Car:
    Mercedes W204 320CDI
    Hi Richard,

    Yes I believe front SAM was coded with Xentry, however, SAM from Ebay was in German. Which made things difficult auto mech said.

    Auto Mech said once he coded the SAM everything worked apart from the lights - the lights are always on, the lights switch to the right of the steering wheel isn't working. It won't turn fog lights on, or turn dipped beam off.

    He put the old faulty SAM back in because he feels a rear SAM is also causing the front SAM to fail? He wants to install both units at the same time.

    Initially, I purchased a front SAM off eBay which worked for a week before failing. Same problems as the first time.

    Many thanks.
     
  4. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

    Messages:
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    Joined:
    Jun 10, 2002
    Location:
    Berkshire, UK
    Car:
    MY04 SL55, MY17 GLC250d AMG Sport
    Theres no such thing as a SAM in German. Xentry Diagnosis doesn't change its language.

    Does your light switch work now he put the other SAM back ?

    What age is your W204 ? The light switch type changed in late 2009.

    R
     
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  5. OP
    OP
    Ritchie18

    Ritchie18 New Member

    Messages:
    25
    Joined:
    May 26, 2018
    Location:
    Belfast
    Car:
    Mercedes W204 320CDI
    No, he said everything worked apart from the light switch. Feels the rear SAM is causing the problem with the lights/light switch? He said it was difficult to code using Xenty because everything came up in German.

    its 08, could this be a fault with the switch instead of rear SAM. Auto mech found water around the rear SAM and thinks it's also faulty and may have blown or caused the front SAM to fail. All these problems began around the time trailer lights when installed. However, I'm not sure there is a direct link.

    Whilst the wipers didn't work with the old SAM, when I disconnect and reconnected the battery they worked for a day. I also noticed you have to be very close to the car for the central locking to work.
     
  6. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

    Messages:
    5,990
    Joined:
    Jun 10, 2002
    Location:
    Berkshire, UK
    Car:
    MY04 SL55, MY17 GLC250d AMG Sport
    Im not sure a failed rear SAM would damage a front SAM. I do however think your rear SAM may be failing.

    I am still not convinced he has proper Online Xentry Diagnosis - if he did then you just code the SAM and it can not be wrong.

    Could be light switch has failed !

    Sadly without car in front of me and Xentry I can not suggest anything further.

    R
     
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  7. OP
    OP
    Ritchie18

    Ritchie18 New Member

    Messages:
    25
    Joined:
    May 26, 2018
    Location:
    Belfast
    Car:
    Mercedes W204 320CDI

    Hi,

    So after replacing both rear and front, SAM's the wipers and horn are working. Central locking also seems to be working a lot better.

    However, still cannot manually turn lights on and off (replaced switch as well) hazard lights, ESP button and heated seats still don't work or seem to have power going to them.

    Unfortunately, I'm not sure who I could take my car to locally that would be able to resolve this issue - may be a Mercedes job :mad:

    Not sure if you could recommend anyone in Northern Ireland?
     
  8. Aaabdulla

    Aaabdulla New Member

    Messages:
    1
    Joined:
    Apr 29, 2019
    Location:
    90808
    Car:
    2010 c200 kompressor

    LOOKING FOR A SAM UNIT, A204 900 96 01, for a 2010 C200.. help anyone?
     

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