I bought a heated seat loom which included a brown, grey, green, white and 2 black plugs. I've connected the brown plug to the plug cluster just above the fuse box. The grey and green plugs are plugged into a cluster block just above the fuse box too (behind the steering wheel to the right).
I've read that the green provides power and grey is the illumination for the switch. Problem is once all plugged in it doesn't seem to work, anyone got any ideas?