I own a 2010 ml350. I’m having electrical issues where my battery gets drained constantly. I’ve put 2 new batteries in, and spent over $2000 at the dealership to correct it. They charge the battery and within 2 weeks the battery is dead again. Is there anything I can do or is it a lost cause ? I’d really appreciate any help.

 

Chasing a power drain on a 15 year old vehicle is something you'll want to do yourself unless your wallet is infinitely deep. Basically what you do is put an ammeter inline between the negative battery post and the battery terminal to monitor what current is flowing. Then you start pulling fuses until the drain stops. It sounds simple when its typed out like that but its far from simple. One of the challenges is that Mercedes hides the fuses in a host of bizarre locations so a task that's difficult enough is compounded by your search for fuse locations. Another challenge is that there will be "keep alive" circuitry that stays powered for some indefinite time after power is nominally off. That's things like your radio continuing to work after you turn the key off until you open the door or the dash staying lit for a short period of time even with all the doors closed and the key off. The point is that the main investment in the search is time and unless you're willing to pay a dealership $200+ per hour for their time you need to do it yourself. Good luck.