My ongoing saga of the test plug not communicating I found a broken wire (Brown) after tracing the wires through at a white plug in the drivers footwell right hand side. Sorted it and it is now communicating and for some reason has also canceled the SRS light. Now found out that I need a new ABS pressure switch.
Davie

Good for you for working it out! Funnily I have that same piece of trim off at the moment as HEVAC harness goes through the same white plug.