W209 c320cdi electrical faults

[rickywalters30]

Hi all.
2006 320cdi 130k
I have lots of electrical faults... mainly radiator fan is on constant with ignition. Main beam is on, indicators don't work. Windows go down but not up. Visit workshop or display malfunction in dash. Starts runs and drives.
I have changed the alternator and swapped the Sam unit. No change
Plus a brand new bosch battery.
All the problems do go away if the battery is removed charged and refitted. But only for a day or so. Or sometimes a few minutes. 13.9v when running at battery terminals
Can anyone help please?
Thanks

 

[Blobcat]

Hello and welcome

Battery should be ~12.4v with engine off and >14v with engine running.
Sounds like battery needs charging /replaced

 

[grahamcol]

As above, new battery time l think. It made a world of difference to my 07 CLK which still had the original battery late last year. You might just find you have the original battery in there too. Oh just re read the op post and see it's already had a new battery. Maybe that's defective or there is possibly a big parasitic electrical drain somewhere. Might need a Star diagnostic and/or good auto electrical engineer.

 

[mattkh]

I have changed the alternator
Thanks

Have you coded the alternator to the ECU..?

 

[rickywalters30]

No... really? Does the alternator need coding?
Battery is brand new.

 

[mattkh]

No... really? Does the alternator need coding?

I am not 100%, but I guess so.