W204 Electrical Problem

[Ritchie94]

Hi

currently have W204 (320CDI 08),

initial problems were:

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

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 felt the rear sam might be causing issues for the front sam.

So after replacing both rear and front, SAM's the wipers and horn are working again. Central locking also seems to be working a lot better. I have replaced the front SAM X3 times now.

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 . I have been to a number of mech with no further progress.

Would it be worth getting my battery tested? Is there any thing that I could be missing?

Could this be a coding issue? Auto mech said he recoded both SAM's before installing.

Could this be a earth issue?

Many thanks in advance!

 

[c270 cdi]

Don't know if it's any help but I had similar problems on my old 2001 C270 CDi. After an accident repair it started doing weird things - headlights flashing when it felt like it, blowers working then not working, interior lights working intermittently etc etc. Took it to an indie down in Hampshire who replaced front SAM which solved the problem for exactly 10 minutes then it started playing up again. Eventually it turned out to be the earth connection in the driver's footwell - when the car was repaired they hadn't done it up properly and it was shorting out - caused the earth cable to melt. Once that was repaired everything worked fine, and to prove it we put the old front SAM back in and that was fine. I kept the car for about 3 years after that and none of the problems ever showed themselves again. May be something you could look at before you buy any more parts.

 

[Ritchie94]

Don't know if it's any help but I had similar problems on my old 2001 C270 CDi. After an accident repair it started doing weird things - headlights flashing when it felt like it, blowers working then not working, interior lights working intermittently etc etc. Took it to an indie down in Hampshire who replaced front SAM which solved the problem for exactly 10 minutes then it started playing up again. Eventually it turned out to be the earth connection in the driver's footwell - when the car was repaired they hadn't done it up properly and it was shorting out - caused the earth cable to melt. Once that was repaired everything worked fine, and to prove it we put the old front SAM back in and that was fine. I kept the car for about 3 years after that and none of the problems ever showed themselves again. May be something you could look at before you buy any more parts.

Thanks for the reply. I am going to feed this back to mech.

It's a ticky one, do you know where the earthing / grounds or on the W204? or the best place to check?

 

[c270 cdi]

Best place to look would be anywhere near batteries and SAMs. Can't be more specific than that but I'm sure someone on here will be able to tell you exactly where they are.

 

[umblecumbuz]

Where are you based? Maybe an experienced Indie could be recommended.

 

[Ritchie94]

Where are you based? Maybe an experienced Indie could be recommended.

Base in Northern Ireland?

Just want to rule out other things before taking it to Mercedes?