Hi... I have a 1994 626 & the windows are fogging up when ever I drive it in the Rain, Fog or Snow. I have checked and my heater core is not leaking. I also thought that maybe the interior was damp from cleaning so have made sure that is dry. It seams to happen when Iam trying to run my defrosters. Any Ideas??? Thanks, Tim in Minnesota

 

Make sure you a getting outside air, not inside air, and turn on AC

 

Check the seal around the doors - mine has a small gap and I get fogging up under the same situations.

Got the car in for its MOT right now and when we get it back will be replacing the rubber seal around the door. Will post if it fixes the problem.