The radio (if MB) has two 12v supplies. One switched by the ignition and one permanent for station memory and to play radio with ignition off. Maybe some leakage there.

20 milliamps isn't too high but for 2 weeks is probably enough. I checked mine after replacing the battery (MB) and got 3 milliamps.

Maybe just put a 'top off' or float charger on the battery. They're only a few bucks at Harbor Freight. Pretty much designed for this problem.

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Good luck.






1998 E320 Wagon