rear defog

the rear defogger has stopped working on my 2003 alero 4clynder engine. replaced the relay, the light still lights up but the rear window stays foggy/icy. what else is there to try? thanks

Check the connections to the window grid and make sure none of the grid lines are damaged. Another common problem is the RF filter module located at the back of the rear C-pillar area or under the rear package speaker shelf.