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Discussion Starter · #1 ·
Hello all,
I'm a new one member here with a 1994 E320 92K miles which I owned for 2 years now. I had no problem with the car until now. All the lights on the dash board are on (battery charge, abs, asc(stability), water, oil sensors and so on). Car died on me, draining the battery. So I figured it was the alternator and I replaced the brashes/voltage regulator on the back of the alternator. Changed the belt while I was under the car and to my surprise the problem did not go away. So I though it also could be a battery, which was drained and looked original ( bought a car with 68K on it so I think it could have been the original battery). I put a new battery there and still the problem would not go away.
Please, advise on what other things might be at fault here. Thank you in advance for any inputs.
 

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perhaps

Perhaps you should be looking at the computer, or the overvoltage protector relay. Have you ever jumped the car or gave someone a jump? Supposedly MBZ are sensitive to over or under voltage.

It should be located behind the engine computer and A/C computer, both behind the battery. It's a silver or black box around 2" tall 1" wide all the way around. Very overlooked relay.
 

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Discussion Starter · #3 ·
Thanks for your reply. I have looked into that overvoltage relay too. Although the fuse wasn't blown, I changed the relay and it was working well, but when I came back in the morning to drive it same thing happened. I think there must be a ground wire loose somewhere, so I"m bringing it to the dealer for diagnostic tomorrow. Hopefully they won't rob me too much :(
 

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Alternator Problem still?

I just joined this board so this may be too late to help or not relevant..however...
I know of a 1986 400SEL which had what sounds like a similar problem. Car kept draining the battery. My friend went through several mechanics and found it was an intermittant problem in which the alternator was actually reversing itself (intermittantly) and instead of charging it would actually drain the battery. Not exactly sure if it was something in the alternator itself but he did have the "seemingly good" alternator replaced by a skilled mechanic and the problem never returned. Might want to mention this to your mechanic.
 

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I just went through the exact same thing that you just described. Still kicking myself for being cheap and replacing the brushes. There were no dash lights indicating an electrical problem either. Anyway, I finally replaced the entire alternator and all is good. Lost out on the additional cost of the brushes/regulator though.
 
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