Hi all - I suspect my FIT is running its AC all the time even when I think it is off. Here are my observations:

1. AC is off. AC button light is off and switch is definitely off. On windshield vent and mixed air modes, the vented air feels cooler/dryer to the touch. On any of the other modes, vented air is equally warm with the outside air. Going from windshield vent to direct vent, the air will feel cool for about 30 sec before it seems to "get warmer".
2. When driving, I notice (with windshield vent on) condensate fogging directly above the vents on the window
3. When parked, I can see water dripping down from the evap pan / compressor area.

Thoughts? I'm the original owner and don't recall this until more recently.
And what is the possible cause I should be investigating here?

 

Most cars use the AC as the defogger. If your AC is on the defrost position your AC will turn on regardless of whether the AC button is on or off.

Try it with any other car too.

 

Is that true?! I noticed rpm kicks up and the engine gets bogged when running defrost, but wrote it off figuring if it's making heat, what's the ac system doing? And for the OP, i'm assuming this is exclusively when the blower (cabin air) fan is on.

I always turn off fans when leaving the car. figured it's like getting up with a backpack on. became a muscle memory thing catagorized along "don't eat Ritz crackers while laying on your back," so i never educated myself.
Reading time!

 

Mine does the same on defrost.
​...I think the owners manual mentions it.

The feature that surprised me.....the auto turn-on of the rear wiper when engaging reverse with the front wipers on.

 

I think every modern car does this (kicking on compressor in defrost mode above certain outside temp) except for my Alfa Romeo 4C.

Conditioning the air removes moisture from the air, otherwise your windshield would fog!