Thanks for the quick response. The car is a '95 16v without aircon.The specific problem I have at the moment is with the heater fan. It has packed up altogether. I have had all the bits out (the fan, resistor block, switch unit) traced all the wires, (theres one that goes up behind the steering wheel that I have no idea what for) and without knowing whether or not the fan takes a positive feed and the resistors and switching is in the earth side, or the other way round, fault finding becomes a nightmare. The fan itself is fine as I have given it a direct feed and it works fine.