As of today I've realised there is part of the switch that isn't visible from the driver's seat position that you need to turn the mirror adjustment dial to so that the heated element comes on and will clear the any condensation from the mirror glass. The dial needs turning 180 degrees so that the dial is away from the default rest position and pointing to the heater element sign - obvious really - at least if you can see it properly!
VW Passat B6 Heated Mirrors Stop Working - Replacing Heater Element Passat Mirrors |
If the heated mirrors on your VW Passat B6 aren't working then this would be a first item to test to check if they can work before taking to a garage for the mirrors heater element to be replaced.