Ford does not want to warranty the defect. They are saying that the conductive lines were scratched off even though the protective paint coat over the missing lines are in perfect condition without any scratches. Ford even has issued a service bulletin about this problem and issued a repair kit to the dealers, but in my particular case the dealer says the missing amount is too much for repair. In fact, of the eleven defogger lines on my rear window only two work, this was reported to the dealer within two weeks of picking up the car.

Next step the judicial system so buyer beware. If you want a new Mustang Convertible, check the rear defogger before you sign on the dotted line.