Rear window defogger quit, light stays on at the control panel.

Often it is the connection between the power supply wire and the grid in glass. That's what happened to my Toyota anyway, all seemed fine, light for defroster on but no heat/defrost

You were right about the power supply wire. At the Right, Front passenger door disconnect and fuse panel, a connector was 'smoked'. Only the contacts for the defogger wire were damaged. Pulled those wires out and bypassed the connector. All the rest of the wire I left in the connector. All is working well. Thanks to GM for another ''well thought out" job of engineering :(

Guys I found out that it's not the fuse it's the harness from the fuse box Chevy Impalas are known for that open the passenger door take off the bottom plastic expose the harness from the fuse box pull it off and look at it

The harness will need to be replaced

The harness will need to be replaced to the fuse box need to be replaced it's burned out i have a 2011 Chevy Impala was doing the same thing