Ok, I live in a pretty warm area so I don't use it often but the few times that I have had to use my defroster it took FOREVER for the window to clear. One time I had to use it the car was already warmed up and it took 15 minutes for the window to clear. I even got to where I was driving and some of the window was still fogged up. Is this normal for the defroster or could something be wrong? I don't have any tint on the windows yet so I don't think there is any interference there. Any input???