So I've noticed this recently... I have my HVAC set to defog, fan on low and the thermostat set to the first blue line (from the center). The AC button is not engaged.

The blowers certainly seem like they're blowing exceptionally cool air. When people ride in my car, they ask why I have the AC on with the windows open...

Any thoughts? It's summer in Chicago so it's 85 and mad humid outside so it's not the outside air coming in... I can't figure out what's going on with the AC.

Thanks.

 

The defroster uses the AC to remove moisture from the air.

 

Ah... that makes quite a bit of sense actually.

 

Pretty normal. We get complaints about that from Nissan owners too...

 

yeah, i try to avoid the defroster, but it hits me right in the face.... my vents are blocked by my arms sometimes.... so i use the defroster...

 

Vent's blocked by your arms? You rocking the 10 n' 2 still?

 

I didn't realize the defrost setting would activate the compressor in and of itself..... I thought you still had to push the a/c button.

I'll check this out today.

 

nope it's automatic

 

no freakin wonder my gas milage is going to crap lol! I run mine all the time! I thought for some odd reason it just blew colder air.

 

Is there a way to defeat the automatic compressor activation?

 

I tried it today and sure enough, just like you guys say. I had 2 Mazdas with manual a/c and you had to press the a/c switch on defog. Guess I just "___"umed......

 

yeah as someone said the a/c compressor runs while defrost is on so that it can dry the moisture out of the air to prevent fogging. if you really like the air comming out of the defrost air openings but don't want the a/c compressor on if you take a part the air conditioner control **** area you should find a little momentary on switch that is pressed down when the right hand **** is turned to defrost. you can cut that wire and put a switch inline with it so that you can turn off the switch when you don't want a/c compressor during defrost. I don't know if anyone has tried this yet on a scion but i have read a write up of someone who did it on another vehicle.