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Battery Drain? 240d W123

Old 03-07-2015, 09:49 PM
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Default Battery Drain? 240d W123

Hi All,

I'm having an issue with my 240d, and I was hoping somebody could point me in the right direction. I recently replaced the alternator, then the starter. After replacing the starter, however, I came out of a bar one night to find a dead battery. A lady gave me a jump, but she had to stop when the cables started smoking. AAA then came and tried to jump it, but the same thing happened. We could hear the bend running this time though, and we gave the starter a tap. We then jump-started the car, and I drove home without a problem. The next day the battery was dead.

I took the battery to AutoZone (I had a warranty). They tested it, called it bad, and gave me a new one. Funny thing though: When they put the new one on, they said it was already reading funny. They tested the (new) alternator, which was "good."

I drove it home without a problem. I started it the next day without a problem, and three more times after that. The next time: the battery was dead again. Totally dead. Flatline.

Anybody else been through this?
Old 03-08-2015, 01:13 PM
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Good call. I'll take a look at those.
Old 03-09-2015, 10:16 AM
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Join Date: Mar 2015
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No, they aren't touching. Unfortunately. That would have been a real quick fix.
Old 03-18-2015, 07:42 PM
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Join Date: Jan 2008
Posts: 553

This is not the only possible issue but when the Glow Plug Relay sticks on a New Battery can die in a matter of hours.

It is a good idea go get one of those $6 or less when on special or on sale Volt/Ohm Meters from Harbor Freigth as you can supply more info.

If that is what is happening pulling the Electrical Connector at the Glow Plug Relay would disconnect the major part of the current draw.
If you had the Voltemeter and the Glow Plug Relay is on when it is not supposed to be you sould see around 11.5 Volts (or less if it has been on a long time). Disconnecting the Electrical Connector from the Glow Plugs at the Glow Plug Relay should cut off the Voltage to them and you should see your Battery Voltage rise.

If there is a short somewhere else besides the Glow Plug Relay and the Starter Cable removing the Fuses one at a time and seeing if the Battery Voltage changes can sometimes give a general area of where the Short Circuit is.
Old 03-21-2015, 03:55 AM
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Join Date: May 2011
Posts: 12

Check your idle / rpm speed we had the same problem with our 300d ,low idle and short 5 min trips over a few days would drain the battery till I adjusted the idle speed

Cheers Anthony
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