Fan blower??? (At what point does the AC come on?)

[debburyl]

I have a Question ? At what point does the AC come on? Only when you press the AC? Because I've noticed that everytime I turn the Defroster on this cooling fan comes on like the AC is on? But if you switch it to the heat the cooling fan don't come on. Is this normal? Or is my AC coming on? The fan under the hood.Also if you turn the temp down at what temp is for AC?

[Messy Mitsu]

Do you have climate control? it's normal for it to do this in the winter if so

[debburyl]

Yes, I think I do. I will ck. why does it do that only on Defrost? And not on Heat? Does that affect your MPG

[ahintofpepperjack]

Air conditioning acts as a dehumidifier. Turning the defrost on above a certain temperature (I forget the exact temp but around 50F) will engage the A/C compressor to dehumidify the air.

[debburyl]

Yea, I knew at a certain point the AC comes on. I never turn the temp down that low. It's just everytime I turn it to defrost this fan under the hood comes on like a cooling fan. But if you turn it to heat the cooling fan stays off. Is that normal for the mirage or should I have it ck out?