One problem related to defogger has been reported for the 2002 Dodge Ram Van. The most recently reported issues are listed below.
Windows fog over dangerously, obstructing vision. Dealer reports that air blend door of heater/defroster is rusted solid preventing the admission of fresh air to the cabin, and thus the defrosters. According to the dealer the door is rusted solid in the recirculate position. I suppose this could result in excess carbon monoxide buildup as well as obstructed vision.