After not having used the AC over the cold winter months, found no cool air pumping when the weather warmed. Local Honda dealership recharged the AC system and it blows cool once again. Have noticed that when the AC is not on (AC push-button for on/off is not illuminated indicating it is off), on Vent I get ambient outside air temperature, but on Defrost the AC pump engages and cold air is coming out (AC on/off switch still not lit up indicating it should be off) and I can definitely feel the tug of the AC pump against the engine as I am driving. No other vehicle I have ever owned has done this (pumped AC when the AC was off using the defroster). Is this normal for a 2006 Civic? If not what is the likely root cause to resolve this?

 

https://www.google.com/search?q=ac+o...+defrost+civic

 

The A/C is always on when in defrost mode is what noobie is hinting at. It helps the defrost a lot, you'll notice when it gets cold again. There's almost always a way to disable it. Try this one: Defrost WITHOUT the AC ON!!! - 8th Generation Honda Civic Forum