Pontiac Repair: windows fog up on 92 pontiac trans sport, pontiac trans sport, coolant loss

Question
I have a 92 trans sport 3.1 tbi. For no apparent reason the windows will all of a sudden fog up while driving. Defrost does not help, or makes it worse. There is no sign of coolant loss or antifreeze smell,HELP!

Answer
Hi, do you have the heater on if so. trun it down, not the blower but the heat. or trun the heat off, trun the ac on to dry the moister out of the car. This base on that the heatr core is not leaking. This happen when the temperature out side is the same as the inside. And when you trun the heat on the humidity gose up and causes a fog on the in side.