@RehanBhatti i changed the temperature switch but it did not turn on the fan at desired time. i took off my old switch, it was full of rust etc - cleaned it and it was shiny again and put it back - and it did not turn on the fan too and needle crossed 70% mark. why is it happening? i have put back the old one and it shows the temperature reading all fine but fails to start the fan on Time - so is the sensor bad itself or what?