Needs to be the right one of the two.

Think it changed at some point in time, can't remember details just now.

If you message me with your VIN I can look into it for you tomorrow. 

T11a pin 10 for your car, built 31/03/2004. It ends up on pin 14 of the 81-way connector at the engine ECU, if you fancy taking a different way through.

 

Same T11a connection for any car built before May 2004 by the looks of it. T11b pin 6 from May 2004.

 

Thanks very much for that! Mega useful.    Although now back to changing the pins around 🤦🏼‍♂️

Team - bit of gen to summarise how I got mine working (probably obvious).

 

T11a pin 10 ONLY (for my pre may 2004 car)  

 

DONT try and piggy back or an ignition wire from the fuse box, this caused a P1689 code for me - use the brake T4d pedal plug, pin 2 as the wiring diagram says and it works!…. Obvious stuff I know.  

 

Ensure you cycle the ignition having activated it via the OBD.

 

  Very many thanks to Breezy_Pete for his time and wealth of knowledge.