black wire with green plug is ign live, blue/grey wire with grey plug is lights on and brown wire with brown plug is earth.
as above the brown goes to a massive round earth wheel thingy near the fusebox, the other 2 go to the same colour jumper blocks which will be back there somewhere, just gotta find em! if you look at plug D on your fusebox all the jumper blocks get power from them so chase the wires from there and you'll get em eventually.
maybe take some pics of what you have, just in case its been bodged
