I usually have my vents set to "Panel/Floor." I had noticed that the air coming out was considerably cooler than the outside air and seemed almost frigid, like the A/C was on. A few times I've switched it over to A/C and the air came out definitively colder, so I thought it was odd but didn't think too much of it. Today I did some testing and found that when the vents are switched to "Panel/Floor" the A/C clutch is actually engaging. If I turn the blend knob up it disengages. If I switch the vents over to "Panel" the clutch does not engage. I've never owned, driven or even heard of a vehicle that does this: the A/C clutch engaging when the A/C isn't turned on. Obviously this is also taking a toll on my MPGs. Surely this isn't normal behavior? Would this be an issue with the switch/controls? ...that's the only thing I can figure.