OK, got to the connector (single brown lead top left hand corner of the boot) but no 12 volts when the rear screen heater is switched on. 12 volts found at the fuse, changed the fuse, still no 12 volts at the connector, swapped the rear screen/heated mirror relay with the slow fan relay (identical), still no 12 volts at the back. Suggests its open circuit between the relay and the connector! Do you know if there are any other connectors in line? When you ran in yor new cable did you run it from the top of the relay straight to the connector? Oh, and how much are the consultancy fees!!!!!!!!