2002 olds silouette - Windows started fogging up on wet days

This may be due to a bad heater core or dirty core with a plugged water drain, first see if the a/c works. turn it on and see if the air gets cold and if the ac compressor works.

The way the defrost works to keep windows from fogging up is that when the front defroster is tuned on the ac should also be on, on most cars when you go to defrost it will turn ac on automatic. the system then uses hot and cold air to remove the moisture in the air to avoid window fogging. if your a/c is not working then that may cause window to fog, but if you are also getting a smell then the drain that lets out condensation may be plugged and then water builds up and also mold from always being wet and when heat is on you smell that.


i want you to run the defrost and when windows fog up wipe window with hand and see if it is greasy . if it feels oily then you may have a bad heater core, the core leaks coolant out and steam and causing windows to fog up with a flim of grease.

Heated air in large quantities is what gets rid of window fog. Make sure you're actually getting hot air out of the dashboard vents, and if not, follow that problem.

Fogging of the windows inside is usually caused by a heater core leaking.
That is located under the dashboard on the passenger side. If you have an odor of anti-freeze or the floor is a little wet on that side, that's a sure sign of it leaking. Have someone check for that.

to defog the glass , run the ac along with the heater
the ac takes the moisture out of the air in the car and the heater dries it out
close of the air inlet so that it recirculates inside the car

check for a broken wire between the door hindges inside the black rubber boot

check the filter<hemodifier>, i beleive you have to replace if blocked

Try to see if you smell coolant when it fogs up. You may have a slight leak in the heater core .

sounds like your heater core is bad check for moisture on floorboard, if found have core replaced ASAP an keep coolant level checked

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It sounds like the computer system is still wet. I would wait a few more days before I panic and hope that it drys out. I don't think it's a fuse.
If you have to have the onboard computer replaced, it can run a couple of hundred dollars.
If you have the engine cleaned again, make sure that the electrical systems are protected well otherwise getting them wet will repeat your problems.