Thanks for this. I have the same year MB Sprinter with the same issue. A new battery helped, but I still get the odd click-no-start happening. I'm going to try your fix next.2010 sprinter chassis for a camper. Had the classic intermittent “turn key no start”. After several cycles would start. No rhyme or reason to the madness. Replace the 8 inch copper “ground strap” between left engine mount bolt and body near left wheel well. $10 or so from the dealer. No more issues. It’s been a month since the repair. Ground strap didn’t look that bad at all, but . . . . Grounds are fickle things.
This forum saved me a lot of money!!!