03' Frontier A/C compressor operation
 

When a defrost mode is selected, The A/C will remain on with the mode control in any mode possition, even if the A/C buton is off.

To turn the A/c off, I have to turn the ignition key off. This is the only way to turn my frontier A/C off.

I was told it is normal by the Nissan dealer service.

Is it true????

Thanks for your opinion.

RE: 03' Frontier A/C compressor operation
 

Are you saying that the A/C stays on when you DO have it in "dash" or "foot" selection? If the A/C is on in those positions, with the button off, it shouldn't be. No pun intended but open the hood with the switch in those positions, truck running and fan on with the A/C buttton off and watch the A/C clutch to see if it is actually kicking on and activating the pump. True indeed however, fog and frost is caused by moisture and your A/C removes moisture from your cab in order to defrost more effectively. Switch the selector to the "dash" or "foot" selection instead of "defrost"; you're killing your gas mileage driving around with your compressor kicking on and off. After you have defrosted, you don't need it on that selection any longer.