1995 Saturn sl rear defroster and sunroof

My rear def. Button does not stay on chk in side case on dash the light comes on but I release my finger and it goes out it used to stay on also I need to clean tracks on sunroof with steal wool they kind of are rusted how do I get the glass off to get to the tracks and do I need to ck something in the switch it lifts up but does not go back