It's that time of year when you get in the car on an evening and the front windscreen has some condensation inside that needs getting rid of before you drive off. When I switch on the front demister blower immediately after starting the car it blows for about a minute and then cuts out, but will come back on again after a short pause. Is this normal operation because the car is sensing that there is no warm air to blow on the windscreen until the engine has warmed up? Or is it possibly a faulty relay which is cutting in and out? Or some other fault? Any help greatly appreciated.