The indicator lamp on the front controls show the rear defogger working, but it would not melt the snow on the window. There was no voltage going to the two connectors at the rear defogger grid on the window. I discovered Chevrolet did not have a separate fuse for this, just a relay in the front fuse panel. Swapping the relay with the starter relay did not fix the problem. To the garage I went. They found a "burnt connector" in the large connector behind the passenger kick panel (near where the other fuses are located). Instead of replacing the complete connector (plus $150), I had them jumper the wire from one side of the connector to the other side. Now it works okay. This problem was caused by: (1) no separate fuse for this electrical device; and (2) bad connection at this connector causing a high resistive connection, thus a burned connector. I was told by the service writer (before the car was checked out) that he had another 2006 Impala come in with a similar problem and it turned out to be a connector in the piller. Imagine my surprise when my problem turned out to be the same. How many people out there have had this problem? I am taking it to GM to see what they will do on this issue. I believe it is a quality issue with this connector block and this individual connector pins along with not being separately fused as with the 2005 and earlier Impala's. Maybe the pin is not heavy enough to handle the current that is passing through this pin.