Hello all... My problem is that my windscreen won't demist, even when blower is on full. I am getting heat and the windscreen will demist about 3rd of the way up, but there doesn't appear to be an even or very powerful flow of air from the vents. The blower motor seems to cycle ok through the speed settings. During the recent rainy weather I've had to drive with the window partially open in order to stop the windscreen from misting over, despite having the blower on full! Will appreciate any suggestions, thank you.