[dmg1]

Does anyone know why the inside of the windows on the front doors frost up so bad when driving at freeway speed. OK when sitting still or 25 mph. I have two vans -1998 and 2002 and they both do the same thing. I can run defrost on high but only keeps windshield clear. Thanks for any help.

 

[97B2500CCV]

Try turning the selector to where it points to your def and vents, commonly called Bi-Level. This should put air out the deforster and vents. The outer vents you can point to your door windows. That should help.

Also make sure that the AC compressor is working. While the Defroster or Bi-Level position the compressor should cycle every some many seconds, it may only turn a few revolutions at a time.

 

[stev]

Stop breathing while you drive. The windows fog too much.

I've tried a few things with minor results to correct this. The funny thing is, I was once an Automotive Engineer for vehicle HVAC systems. These vans sure have me stumped as to when the fogging and frosting happens.

The best thing to do is to open the front passenger window 1/2-inch while driving.