Hi. I just registered in hope for you guys to help me - I would really appericiate it as we two have the same problem!
I also tested my wires, all showed 0volt when no ignition. Ive tested the cigarette lighter thing, it had 14.4 volt when car was on.
The green wire showed 14.4 volt aswell when using the metal in the inside the dash - however, no reading when tested against the black one.
The red wire showed 8.8 volt when checked against the black wire.
Mod edit: I have a Citroen C-Zero 2011
Again, I would really appericiate your help!