Air Con Question...
 

I've noticed that when I have the vent on in my car, the compressor is engaging. Same thing when I have my defroster on and my "mix" on as well. I would assume that the compressor would come on only when I hit the Max or Normal Air switch. Would some of you guys do me a favor and turn your cars on and see if the compressor engages while on defrost , vent, and mix please? Thanks

FT

Not knowing what year your car is, but most compressors come on when the defroster is on in order to suck out any moisture that may cause the windows to fog.

In the Mix position, some air goes to the defroster, which in turn causes the compressor to engage.