I have a 2000 Dakota 4x4 with 3.9l engine. When I use the AC or heat there is a bad moldy smell that comes in the cab for a good 5 minutes. When the engine warms up and I haven't turned on the fan yet, there is a plume of steam rising from the center vent on the console (the one with the adjustable air direction). When I turn on the fan the steam blasts into the cab and all the windows fog up and it takes forever to clear the foggy windows. My floors are dry so I don't think I have a coolant leak. Any suggestions as to what might be wrong???

 

you most likely have a leak in your heater core.

 

yep!!

 

can you hear a liquid sound comming from the dash area?

 

a leaking heater core fills the ribs with coolant, so when you cut on the air it will blow a mist of coolant on your windows.
and it smells moldy too.
put this in the dakota section and they can help you with replacing your heater core.