Nissan Repair: 2004 Xterra A/C always cycling, c switches, winter temps

Question
I have an 2004 Xterra SE with 47000 miles. I've noticed that the A/C compressor engages when the switch is off and the fan is on. No, it isn't in the defrost selection when this happens. I have yet to check if this happens when the fan is also off but I assume it does do to the avg 14 mpg I'm getting in the winter temps. What should I start eliminating first as a cause? The system functions properly when A/C switches are selected.
Thanks

Answer
Charles,

There is a feature to kick the airconditioning on automatically when you turn the air on.  Have you tried to turn the airconditioner off by pressing the button after the light comes on?  If it has not always worked this way I would assume the module would be defective.