my 1998 cavalier 2-door rear defogger quit last week. When the button was pressed the only thing that happened was a quiet click from the internal relay in the defogger switch and no light -on operation. My fix involved removing the heater control panel to check the switch operating circuits and there I found a burnt purple wire ,the actual window power wire,on the switch wiring connector plug. Although a proper repair should involve replacing the wire terminal and the plastic wire holder I got lucky by careful cleaning of the male terminal and with di -electric grease applied to all the terminals. Its still working and my fingers are crossed. As a side note the removal of the heater panel was not a simple task and usually the panel bulbs dont like to be disturbed ,so be nice!