I had a battery problem on my '94 SL 500. I checked all over the place for current leaks, i even removed all the fuses and the battery still went dead in 3 days. New battery, old battery did not matter, they all went dead after three days. Took it to an electrical shop, they said there was a service bulletin about the ignition switch being defective,wanted to do a major dash teardown to access the ignition switch, i declined the service. researched for days on all the Mercedes forums, finally went to a Chrysler forum, everyone universally agreed fused diodes in the alternator. Haven't a clue what a diode is or what it does, or where located in the alternator. Replaced the alternator the next day, have not had a problem since. In my case yes it was a defective alternator. You can buy one of those battery minder things that when the voltage drops below a certain voltage it disconnects the battery around $70.00. Repeated deep discharge of the battery reduces battery life. Unless you have a current leak somewhere else it's most likely the alternator. I agree with your automotive experienced friends.



'87 560SL 150,000
'94 SL500 40,000
'91 350SDL 514,000

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jcciem
'94 SL5000 60,000
'91 350SDL 545,000
'91 350SD 197,000
'00 E55 AMG 77,000