Originally Posted by elsolo
Replacement glass should fix that problem.
My old 07 Taurus had the same issue. And after trying just about every option in the book I was ready to give up and bring the girl to a "specialized glass mechanic". It would have cost me $500ish. But I decided to check a scrap yard and bought a used rear wind shield. Cost me $50 if I remember right. I brought that and the Taurus to a mechanic friend. A couple hours later I had a "new" rear window and a working rear defrost.
This is what I reccomend. I bought a few different "rear defrost repair kits" at Canadian Tire, NAPA, and Walmart. None of them really done the job. But replacing the rear window done the trick. I know that this may seem extreme but it is seriously worth it!