What does it mean when your car is fogging from the vents near the windshield window?

PatrickDoleman

New member
I have a problem with my car its fogging my windshield from the vents used to defrost the window during the winter. It fogs up my whole window and I constantly have to wipe it so I can see where I'm going and it gets worse after it has rained. One thing I know is that my compressor for the A/C needs to be fixed. I think it has something to do with that but I'm not sure I don't know much about cars.
 

HillClimber

New member
Does not sound like anything to do with AC. You either have a heater core or hose leaking, or you have managed to build up a lot of moisture in the car - like water soaked rugs from rain, cleaning or spilling a bunch of liquid. "Worse after rain" points at looking for a leaking door.window that allow the rain to run down and soak into the carpet. Check for door leak. Try hosing the doors edges and all the windows. May be you need to replace/repair door gaskets. If it's the heater, pick up on the sweet smell or touch taste to the tongue.
 

MichaelS

Member
Nope, probably nothing to do with the AC. It sounds like you have a leak in your heater core behind the dash.
Even with a bad compressor, try this, if you have a MAX/AC position. Turn it to there and it should close the heater control valve and stop the fogging. That will show that you have a leaky heater core.
 
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