The Sprinter van’s starter battery is under the driver’s feet. If you see a battery under the hood, it’s an auxiliary one. Connecting another car’s battery to it won’t help with starting the engine.
But you don’t have to tear the van apart to jump it – Mercedes gave you a special connector in the engine bay.
This seems to be a constant confusion for Sprinter owners – either they see an empty space on the driver’s side of the engine compartment and wonder where their starter battery is, or they see a battery there and assume it’s the starter battery.
Unlike most cars though, the Sprinter’s starter battery is in a compartment under the driver’s feet. You have to undo some screws to remove the footwell plastic and then lift up the rubber floor mat to expose the lid to this compartment.
If there’s a battery under the hood, it’s the auxiliary battery. It’s the same type of battery as the starter battery, but when the engine’s off it’s not connected to the starter at all so it won’t help to get the engine going.
You don’t have to rip the cab floor apart
Because the starter battery is so hidden, Mercedes provided a place where you can clip jump leads inside the engine bay. It’s the red mushroom shaped thing just in front of the brake fluid reservoir on the top of the engine block.
Turn it and push it in, and it’ll expose a live terminal. You can connect the positive jumper cable here.
Just clip the negative jumper cable to an exposed metal area of the engine, and you can jump the van just like any other car. If you want, there’s a special brass bolt attached to the driver’s side inner wheel arch just above the aux battery location. It’s a great place to clip the negative jumper lead.