Hi Peter & others
See if any of the info in this attached Doc is of any use as to the central locking wiring in the 02-06 2.8 JTD Ducato, Info & Diagrams are for both with the Factory alarm fitted & the standard central locking for the cab chassis. Athough I thought you already have had this info & been down this track with an alarm & the central locking wiring before.
Cheers
Let me know if it is of any use or if you've seen the info all before.