Weird Alternator/Electrical problem
Thread Starter
Senior Member
Joined: Feb 2011
Posts: 321
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From: LA/San Fernando Valley
2003 C230K Sedan
Weird Alternator/Electrical problem
I keep getting a Battery/Alternator sceen on my car. I changed the battery about a week ago but the alternator seems to be acting up. It makes a spinning/crackling noise then I get the service screen. My radio also doesnt work (no volume but has power) The weird thing is that it only happens sometimes. I checked the voltage using the dyno mode and im getting 12.7 off, 13.2 on and 12 under load (ac, light, etc) but when I tried it under load again it was staying at a steady 13. Im thinking the alternator is going bad but idk because the car starts fine and seems to be charging 
Super Member
Joined: Dec 2009
Posts: 931
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From: LA
'05 c230 Kompressor SS Mistress
It you're alternator if you changed out the battery .. early stages it will come and go like that then it will die out .. replace that sucker and you will be good .. make sure you get the same brand as the one that is on there .. it will either be a Valeo or Bosch .. stick with the one it came with.. good luck
Super Member
Joined: Dec 2009
Posts: 931
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From: LA
'05 c230 Kompressor SS Mistress
hmm I have not heard of anyone that has tried it .... i have only heard of members keeping in the Valeo or Bosch .. even then when a Valeo has been replaced with a Bosch .. like what I did .. I got the alternator warning light again .. put the Valeo in and it was fine .. other members have experienced this as well ..but wait and see someone elese can shed some light on the duralast for us I'm sure
MBWorld Fanatic!
Joined: Mar 2004
Posts: 1,175
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From: Boston, MA
'14 ML350, '13 C220 CDI, '07 C280, '98 ML320
Make sure you get the new battery with the same AmpereHour (Ah) rating of the original battery. Other than that, warranty is another factor to concern.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 3,714
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From: 1 hours drive north of Sydney Australia
2007 W204 220CDI Classic Sedan
Have you opened your bonnet ? . Check where the noise is coming from . Alternator belt? , alternator bearing or elsewhere.? Put a voltage meter across your battery terminals under the different conditions .Check with an auto electrician before spending your money on an alternator . Could be the voltage regulator.
Good luck.
Good luck.
