While driving the vent fan automatically turns on to the lowest setting. I turn the knob to shut it down the in a couple of seconds the vent turns back on.
After turning the engine off and starting again everthing appears to be back to normal. Wth?

 

happens to me as well on occasion, I turn the temp dial a bit up and the vents stop coming on.

 

did you set your air temp preference to floor/window? mine doesn't blast my face with hot air - I like it that way.

 

I leave mine on AUTO all the time, AC enabled winter or summer. Keeps the inside climate under control. The Infiniti had an OFF setting for the HVAC. Never understood why.

 

I've pushed the "off" button a few times - usually when most of the windows are down and what's the point of it being on.

 

What 'off' button?

 

The "OFF" button was removed with the LCI update in 2008. Pre-LCI cars had an "OFF" button. To the OP: My car had the same problem; it was a faulty climate control module. I think they had to replace that entire climate control panel on the dash. Funny thing is, years later it still happens every so often.

 

This has been happening to me lately as well. It will come on randomly, sometimes 3-5 times in a sub-20 mile commute. Would CPO cover this?

 

Exactly. Happening to me for a few years. i shut it off and it seems when I take a corner had it comes back on. Doesn't happen all the time. I don't care about it enough to investigate.

 

That was happening to me. After some research here, I found out that if you turn up the temp dial the ac will stop from coming on. That worked for me and hasn't turned while driving again.