One problem related to rear window defogger has been reported for the 2000 Saturn LS. The most recently reported issues are listed below.
The rear defroster in my car turns off automatically after about 10 - 15 minutes. I have found this design to present a dangerous situation to me when I operate my vehicle during a snow storm. During a snow storm, the rear window in my car fogs up unless I continuously run the defroster! (I believe this problem will occur in many car models. ) my defroster turns off without warning. I don't realize I have a problem until the window fogs up making my visibility very poor. I then have to try to grope for the defroster switch to turn the defroster back on. When I am forced to reach for the defroster button when driving on an icy road, I am putting myself in danger, especially if the sun has set. During a snow storm it is important to be focussing on the road, not groping for a switch every 10-15 minutes. This defroster design has two disadvantages from a safety standpoint. First, my rear window repeatedly fogs up unexpectedly at very critical times. Second, I am forced to divert my attention from the road during the worst type of driving conditions in order to turn on the rear defroster.