Troubles continue with Mercedes C240.
I just replaced my battery 2 days ago. Trying to start up this morning, no luck. Dashboard is dark, no single sign of electricity running.
Any ideas?
Thanks in advance

 

First thing , any time i have replaced a battery without replacing the alternator too battery dead due to insufficient charging from alt.
second if alt's charge is sufficient you have a short, very difficult to trouble shoot visually inspect all cables primarilly those at moving parts ex: trunk doors etc.. good luck hope it is just the alternator.

 

Thank you for the prompt response. I did exactly what was told but did not see any suspicious thing. The battery is well connected. Before changing the battery, the lights and radio were still functioning. Now with the new battery on, the car started for 2 days and nowt he lights are no longer working like before nor the stereo. The car give the impression that there is no battery connected! Any suggestions?
I would appreciate it. Also is there any warranty on Alternator (like a certain mileage where some parts are still covered? ex : the cat iconverter is covered for up to 80K)

 

I recently talked to a friend who runs a MB shop and he had the exact same problem on a c class. The problem was the electric seat modules. He said that when they go bad they might or might not work but they will kill the battery in two or three days. He said they were about 1200 each though.

 

What you have is a high current draw... Something is staying awake when it should be sleeping... Most common are the seat control modules. There is one for each front seat. If your friend payed $1200 for one seat module, then he was rapped in the @$$ with no lube.. There are also many other components that could cause draws. SAMs (fuse boxes), Command Units and much more. Its not that hard to diagnoise if you have the right tools.

 

Had the same problem. Here are my 5 cents, just for the records, perhaps this information will be usefull.
One day my battery died. It's a 5 year vehicle so I said to myself - it's time to replace the battery, particularly it's 20F outside.
Went to the nearest bodyshop, replaced the battery. Next morning it's dead (the battery dead, the bodyshop is still in business). They said there was a drop of voltage from 12.6V to 11.5V and they strongly suggested to raplace the battery. I think it was a wrong move.

Went to MB dealership. It took them 2 hours to figure out where a leak was. It turned out - it was electrical front seat module failure (passenger side). Cost - $350 plus labor.

That's exactly what was described on this forum.

 

Had same problem with my 2001 c320
purchased new battery but it would be dead if I did not drive it every day.
Took it to dealership and they found that the power seat was draining the battery.

Replaced power seat control module...final cost ~555.00( $100 diagnostic, $100 seat removal, $304.95 module and $50 switch) ( I think I got robbed)
did anyone else have the same problem??

 

I had the same problem with my passenger p/w seat module. I unplugged all the cables underneath to keep it from draining the battery. I haven't replace the module yet, still search for a cheap replacement.