When I press the front defrost button, if the A/C had been off (I never use Auto) the text on the display that says A/C Off disappears and the compressor turns on, as I expect. When I press the button again to turn the defrost off, the text that says A/C Off doesn't reappear in the display, and the compressor is still running. I have to press the A/C button to turn the A/C off, and then the A/C Off text appears in the display. Is this normal behavior? It's been this way since I bought the car last October. In my 3G (never used the Auto in that car, either) when I'd turn the defrost on (if the A/C wasn't already on) the compressor turned on, and when I turned the defrost off the compressor also turned off.

 

Yes, this is the norm for our 4G TL.

Switching off "Front Defrost" won't turn off the A/C. You'll have to physically press the A/C button to turn it off.

 

That's a bug, not a feature. Another thing for the "Things I don't like about my TL" thread.

 

While some Acura owners may consider it as a bug, but Acura is so proud of this feature that the HVAC on the current generation MDX is also factory programmed the exact same way; and presumably on all latest generation of Acura vehicles as well.