I recently had my stereo upgraded on my 06 Evo. I noticed after the install that when I select the defroster the air conditioner will also come on. The A/C light does not glow, but the idle speed increases about 200 rpm (from 1000 normal) and I can feel cold non-ambient air coming from the defroster outlets. If I select any of the vent positions the rpms are at normal level and the A/C does not come on.
So being a cause and effect guy I suspect the installer got something wrong. What should I look for in order to fix this? Yes, I do plan on taking it back to the installer, but I want to know what it is before I take it back.
Anyone have any ideas of what I should look for?
Thanks!
MAX

 

I swear that's normal... my 99ecplise was the same as is my fiance's mazda 6 my dad's odyssey and my 08 X.
maybe it was unplugged and when the stereo was installed he plugged it back in not noticing... maybe.
second opinions?

 

That is the way the defroster works, it uses the A/C to condense moisture out of the air.

 

perfectly normal.

 

Ok, Thanks! If it's normal that's cool.

Thanks!

MAX

 

just for giggles I'd like to see the installers face when you reamed him out about it. make it a prank? post a video?

 

Completely normal, air conditioning was a happy side affect of developing a system to defog windshields.