My 1992 Benz 300 SE can't start. It was dead, no lights, nothing. Replaced battery and it started. Following day tried to start it and it was dead. Appears battery was totally drained. What could possibly be the problem? Need help, advise.

It could be the alt. have it check at the zone.

+1 on alternator. Also, check the wiring to the alternator and make sure they are connected. I had that problem where I upgraded my alternator to the 120 amp and beefed up the wiring to 2 ga. but the end connector was cheaply made and it broke and my battery drained. Cut the cheap ends of the wires and just wounds it around the alternator terminal and covered it with fire proof aluminum tape and then wrapped it in electrical tape. All is well now. If it turns out to be your alternator, I would suggest upgrading to a larger amp if you are ruining the 80 amp one. You won't regret it.

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1990 190E 3.0L

if you have no tools spit on the battery post.Sometimes it will make connection

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Also check for power drains, any lights not turning off? Trunk light? etc?

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Likambi, remove the voltage regulator from the back of the alternator and inspect the length of the brushes. It's likely the brushes are worn down to nubs and you need a new voltage regulator.

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Fred Hoelzle

Make sue the lower harness in not shorted, if bare wires contract with each others or body frame. It will drain your battery. Do some of the dash light stay on.

Jack