None starter - Engine service now

[Ianflattley20]

I have a 2015 ford transit custom 2.2L its a none starter. After multiple different people looking at it and a new BCM and ECU all coded correctly to the van but the issue still persists.
Today I have managed to get the van started with the help of a mechanic. The only way it will start is if we put a 12V supply onto pin 2 of relay R18 which when I look online is the High-speed cooing fan(is this information correct?) When the power is applied all the faults on the dash dissapear and the van starts no bother at all, as soon as the supply is removed the van cuts out.
All error codes point to no comms with the PCM and BCM.
Can anybody shed any light on this issue for me?

See picture of 12v supply which allows me to start the van.

[Altransit]

How many batteries under the drivers seat

[Ianflattley20]

Just the one

[Altransit]

Have you tested the main fuses, and the connections, in the battery fuse box behind the seat

[Ianflattley20]

I have checked all fuses and they are all good. I need some wiring diagrams do you know where yo find them?

[metalworker0]

JUST IN CASE - well if you have the 2 litre mixed up with the 2.2 ..then that relay would be a Diesel: Powertrain control module in the 2 litre, which if in fault would stop it starting.

if by any chance you are wrong ..fuse related to that would be f30 and the engine would be an ecoblue engine .

all the best.mark

[Ianflattley20]

Just an update. I have checked all the relays across the top of the fuse box and all don't have power to pin 1. If I put power to pin 2 of the grey relays
(15 and 18) my issues go away and if I put power to pin 5 of the black relay (17)