ok so today i was driving my car and i had the ac on and i noticed a fume coming out of my vent, really only the one above the radio. i pulled over to make sure nothin was wrong. i popped the hood and saw nothing wrong. so i thought maybe its just the ac. it was almost like a vapor because i couldnt smell it and it was a fume almost comparable to your breath on a really cold day (except a little bit less visable) and on my far right vent i noticed around the vent it was a thin layer of mist (no water droplets it just felt damp) i couldnt find anything in the search so any help would be great

 

Same thing coming from your vent...only backwards: Warm moist breath hits cold air = condensation (you made a cloud buddy!)...for the ac, cold air hits warmer moist air in cabin = condensation.

If you want a really scientific explanation...google "dew point"

 

happens a lot on moist, hot days.

I think the car does it when your ac fan activates (again, on a moist day) - happens after WOT (ac is off during WOT, as far as I know), for example... is my logic correct?

 

lol wow i just wanted to make sure it wasnt somethin else, in my year of owning this car i never experienced that even on alot hotter days, i figured i was just makin clouds but the weird thing is my dumb a$$ was kinda freakin out i started thinkin maybe this isnt good for me to breath. i felt like i coudnt breath and i started to cough a bit so i closed the vents and started sticking my head out the window lol. wow the power of the brain gotta love it, you feel like your dying and nothing is even going on. but thanks guys and if anyone has anymore input thanks.

 

my truck started doing that when I had a hole in the heater coil...
you might what to check that

 

what problems come with that and i dont even know where to look for a heater coil

 

If there were a hole in the heater core you should smell the coolant. And you would see coolant loss plus the car is likely to overheat in traffic.

 

none of those problems yet

 

It's normal.

 

good to know its normal ive just never seen it before nor was it really that hot