Greetings everyone,
thank you all for your suggestions much appreciated. I have now fixed the problem. I managed to get a print out of the "Auto Data" test procedure for 1990 2wd Cossie which provided me with all the resistances and test point voltages of the whole system, this however all checked out ok. Also working from the wiring diagram I managed to trace the fault to a broken wire in the loom which feeds one of the relays.



Abs ecu modules are in fact different, there are different colour multiplugs and sockets also the plug sizes are different so I dont think you can physically connect the wrong type unit.

Also there are major differences in the wiring and relays between the years on the Sapphire models. I dont know exactly what they are as I have only concentrated on the 1990 2wd model.

I live in South Devon and the local Ford Dealer wanted £86.50 + Vat to do a "diagnostic plug in" for the abs system.

MOT tomorrow and back on the road