Windshield fogging inside on a 1996 Dodge Caravan

My daughter has a 1996 Dodge Caravan. When it is cold out and she turns the heater or defroster on the windshield fogs up on the inside. I told her I think it's is caused by a leak in the heater core. Anyone else with any other ideas? Thanks


Response:
This depends on IF the van has an operational Air Conditioning System. This "Fog" is caused from Air Density changes. When you first start it up and turn on the Defroster(hence the name) it also turns on the A/C Compressor. Pop the hood and watch the compressor clutch. Especially these past few days. But this SHOULD evaporate within a couple minutes unlike Anti-Freeze.

Defrost only on high and still wont clear up.

2001 LHS. Windows are fogging up in back. Defrost only on high and still wont clear up. Driver only in car and nothing wet inside. Does this model have an air exchange door that I can get at to check if it is stuck?

Answer:

You have it correct, the recirculation door for outside air is stuck closed and not allowing air to come in causing the fogging condition. The motor for this door is on the passenger side of the heater box. I believe that you can see this if you take the glove box out, but it has been a long time since I've worked on one of these for this issue. It is motor number 2. As I looked at the instructions it says the dash has to come out to get to this motor.