If its the original battery, I'd put my money on that first. Start with the cheap odvious stuff, like a 7 year old battery.

Yank it and bring it to an Autozone they will load test it. Or you can call MB roadside and they will replace it, usualy for only the cost of the battery plus tip, so not a bad deal.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200