Hi, the light on the switch is not always an indication of power going to the heated screen!! on models that do not have a timer relay controlling the heater, the light only means the switch has been turned ON, but on models with the timer relay, it is an indication that the relay has energised and power is going to the heated screen.
The most common failings are:- the heater element in the screen has broken, one/both of the connections from the element to the car wiring have become detached from the screen, or the tailgate earthing is poor (often also affects rear wiper working)
If you want a copy of the wiring diagrams contact me on nige110162(at symbol)hotmail.co.uk
nigel, February 2010
