My wife has a new 2016 Nissan Altima. She thought she had an doctor appt today [wrong date] and there was a heavy dew last night. I fully expected the rear window defroster to dry up the dew. After about 10 miles there were clean lines so you could kind of see thru the back glass. It took another 5 miles or so before the back glass was mostly clear. Her previous car [2003 merc] would dry up the dew in short order [mile or so] miss the mirror defrosters too! I'm thinking I might need to take her car to the dealer but I don't want to waste my time if they are going to say that's normal. I do intend to try the defroster out again sometime but I don't drive her car all that much.

Can you tell me how to apply RainX without leaving a windshield with smears. I have cleaned and cleaned the windshield and finally gotten rid of the smears from my first application, but I think I took off all of the RainX. I applied it as instructions. That is, wipe on with a clean cloth, let dry to a haze and then sprinkle with water and wipe off with a paper towel. When driving into the sun the next day, it was like looking through a cloud. any suggestions?