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My battery has been dead now several times on this S320. took it out and had an load test done and battery still good.
Put back in fully charged. Next morning dead again. Used multimeter on milliamp setting and did draw test with neg. cable disconnected.
Meter showed an amp draw of 2.4 amps at which point I pulled every fuse one at at time from fuse panel under hood and also in the trunk.
I could not get the meter to zero out at all. You would think as I pulled the culprit circuit fuse then the meter would go back to zero.
I am rather stuck now and not sure what to do as the battery is still going dead. I checked battery voltage last night and it was @ 12.01 volts.
Twelve hours later it had dropped overnight 1/2 a volt to 11.5 volts.
Checked alternator during the course of all this and it is putting out almost 14 volts @ idle.
Any help in direction I should take would be greatly appreciated!
 

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So with all the fuses pulled it's drawing that 2.4? Or one at a time only? I'd pull all of them, then I'd look to be sure there isn't another fuse box somewhere because I think all the Benz I've owned had at least two. Each side of the dash should have a cover, might be in there. Or below that spot where your feet would hit the side should be another cover. Might be in the trunk, like behind a fabric door on the sides or under the floor by the spare tire. Could be under the dash too. If all that fails I'd wonder if it's the alternator itself, but I can't recall one ever doing that. If all fails I guess I'd start looking for something that smells or is warm because that's 25-30 watts which will be warm, maybe even hot, and my be cooking some part of it which I'd imagine will smell.
Search for warmth by feel but ideally with a thermal camera. I've got one a work and I have an IR rifle scope, both can spot anything warmer than the surroundings. They also make them that plug into a cell phone. My friend has a FLIR for his phone and it's pretty impressive. If you have a friend that just has to have the latest tech, like my friend, I'd ask him. I'd be PC and say "him or her" but I've yet to see such a device owned by female.
Meanwhile I'd keep it on charge or disconnect the + side when not driving because that much draining over and over is very hard on the battery.
 
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