The two most common possibilities are a plugged up condensation drain for your air conditioning, and a leaking heater core. You will usually smell antifreeze from a leaking heater core.
Another less common problem is a leaking windshield gasket.
It's a Dodge thats why.
Check your heater core under your dash.
passenger side floor board
The Battery is located in the Floor board between the driver and passenger seats, you will have to remove the rubber floor to access it. Special tools you may need are on the passenger side in the floor, where the jack is.
Water is leaking on passenger side floor board when heat is on
It is on the bottom of the passenger side of the dash. Look up from the passenger floor board and you will see it. It is held in by three bolts.
The trunk release for a Dodge Stratus is to the left of the drivers seat when sitting in the driving position on the floor of the car just inside the drivers door. Pull the lever and you are in.
this could be from the heater core. When the heater core goes out it leaks....right into the passenger side floor board If it is water, not coolant, the problem could be a plugged air conditioner drain. Easily accesible from under the hood.
Roll up the windows!
sounds like you need to replace the heater core
Crack in the heater core
If a Dodge Ram Van is not getting any heat, the first sign of it being the fault of the heater core would be a very wet passenger side floor board. The heater core is located near the foot well on the passenger side.