My defroster does not appear to be working properly --it is blowing hot air but windows still are fogged up during rain

There is too much moisture inside the cabin. Either something is leaking water into the car, or your fresh air setting is not working on the hvac system. You can not run the system on recirculate and get rid of the moisture.

Heater radiator leak.It is under the windscreen and can blow hot water (vapor) to the glass.Does it slightly smells heated water?Very rare:rain water in the saim compartment as the heater having the same simptoms.Track the problem,ceck coolant level regularly.Cheers,hope u deal it,let others know.

You are getting feedback into your Resistor, You need to located the Short...

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.

Is the a/c working ? The a/c helps dry the air blowing on the glass in defrost mode.

Make sure the vent system is set to draw air from outside. If it is set to recirculate the same air that's inside the vehicle without drawing fresh air from outside, the resulting humidity that builds up inside the vehicle can fog the windows even when you run the defrost. You can also try opening the windows a bit to get some more air moving inside.
If it still fogs when the vents are set properly, you may have a leaky heater core. The heater core is a small radiator that is located under the dash that the heater system blows air through to heat the inside of your car and provide heat to defrost the windshield. The fog may be coming from the heater core leaking hot coolant steam that's being circulated through the defrost system. If this is so, you will need to replace the heater core.

buy better blades & get some rain-x put on windows it works & wipe blades w/it too.

While in defrost mode press and engage a/c button on dash(leave in hot air position) and see if that helps with defrost issue. What this does is with a/c operating it removes moisture from the air in car which is all fogged windows are is humidity build up.Dont worry cold air wont blow through vents even though a/c on due to position of hot/cold adjuster.

Was there a smell along with it fogging up the window like antifreeze? If it did the heater core is leaking and needs to be replaced. It will be kind of a sweet smell.