One problem related to defogger has been reported for the 2004 Dodge Ram 3500. The most recently reported issues are listed below.
There is an exhaust leak coming through the air vents when the hvac fan is turned on. I was a little dizzy & had a headache after a long drive back home from san antonio. After talking to a physician about my condition, he felt that the cause was most certainly carbon monoxide poisoning. I have mentioned this problem to the dealership & they have been unresponsive. They say that they have never heard of this problem before & there is no fix. I've researched the internet & found many others that have experienced a similar problem so I know I'm not alone. There is even one gentlemen that believes he has the fix. Apparently Dodge didn't cover some of the holes between the engine compartment & were the hvac system draws fresh air for the cab. This needs to be fixed as this may injure someone terribly.