Sprinter won't start

Hi there I have a 2006 sprinter 311 new shape (906) the van has been sitting for 3 months and now won't start, I recharged the battery and nothing then bought a brand new battery today and still nothing. I even tried to bump start it but nothing. The van just turns once really slowy then nothing, no crank. I also changed the starter relay fuse but still the same any help guys?

Re: Sprinter won't start - Euro 2006

As time goes on, and corrosion/service cycle takes its toll, there is some history of a problem with the NCV3 heavy "Y" cable.

Some info is here.

https://sprinter-source.com/forums/showthread.php?p=86851#post86851

General information only. Not intended as a diagnosis.

vic