So things haven't gone quite to plan. For one glorious moment I seemed to have control of the extra pack relay controlled via the leaf itself with a separate breaker switch on the dash.
Unfortunately on restart I now have errors:
P0AA4 0009 EV/HEV QNRH Hybrid Batt Negative Contactor EVC - 151
C118C 0109 ABS EV/HEV System BRC-126
C1A6E 0109 Brake EV/HEV System BR-146
C1A70 0109 Brake Control System BR-160
All of the C codes appear to be related to the regenerative braking system however the P0AA4 seems a little more concerning and may represent a main contactor that is persistently shut (perhaps opening and closing briefly while the new relay was turning on and off - enough to weld itself shut). With a little coaxing and use of leaf spy I can clear all error codes and get the car moving and charging but on turning the car on again the errors re-appear.
I need to find a day to troubleshoot this as it may simply be that I have created a short at the data connector by accident or even overloaded the VCM. Hopefully have some answers by Sunday. If not then I'll need to drop the main pack and check the main contactor.
Talking of which - does anyone know anyone who might have a spare contactor that I could buy from them in the UK? I can source one from America but it won't arrive until 1st March and I'm achingly close to getting this all working.
I'm now beginning to wonder whether I need to use a small relay that sits in the positive wire of the main relay controller so that there Is no fluctuation in power signal to the main pack relays, (and no chance of shorting) I can then use this relay to deliver power to the new pack relay i.e. from the leaf's 12v battery. Lots to think about.
Just hope it's something that is easily rectified otherwise it's going to be a fairly embarrassing visit to the dealership to get the VCM replaced.
I'll keep you updated if I have any breakthroughs. All I can say at the moment is... don't do what I've done so far - because it clearly doesn't work