I have 2003 TD6 the gearbox ecu has 2 Red blue cables feeding, it which according to the diagram should have 12v on them via a 30 amp fuse from the battery. The fuse is in the engine compartment fuse box. Can anybody tell me where this box is or where the fuse as I have no voltage at the ecu

There is a big black box on (your) drivers side under the hood. It is just behind the headlight next to the wheel arch. It has a big cover on top that is screwed down with torx screws. In their you have the gear box ECU, transfer box ECU and a bunch of fuses, relays and connectors. It is very easy to get to and work on.

Good luck and keep us posted please. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

Thanks
I found it shortly after sending the message.