Exactly as the title says... Is this a common problem cause its definitely annoying, and with winter coming up that thing will be on alot more.

 

That's an easy problem to diagnose. I had the same thing. There is a short in the grid on the rear window. Where is the question. Mine was under warranty. They replaced the window. Maybe someone else can help you trace it down. Has there been any repair done to it? Does all of the elements work on the rear defroster?

 

Hmm, ill have to check it out. I dont know if the entire window defrosts, I've never noticed differently. I had just removed the On-Star antenna this summer by unscrewing it so I don't know if that could do it. First winter with the car so I don't know its history. Can I check the lines with a multimeter or are they somehow embedded?