1996 Maxima GXE, manual A/C unit, Automatic transmission. 200,340 miles.
When I press the control button on the dash for defrost air, air comes out the defrost vents.
When I press the floor button, air comes out the floor vent.
When I press either mix button or the dash button nothing changes, if its on the floor it stays on the floor. Same with defrost.
Its been this way for 2 months.

I just now went out to the car to make sure I had this correct and all the buttons are working....
I hate it when it fixes itself. Any idea what it might have been so I can stop it from happening again?

 

Those push buttons are electrical switches. It is possible that the metal electrical contacts in the switch got a layer of tarnish on it and by pushing the button, the moving causes a wiping action that got rid of the tarnish. There is no way to stop the tarnish from re-forming other than keep pushing the buttons. But in reality, if the contacts are developing tarnish, the coating that is put on at the factory is wearing off. Replacing the switch is the only option besides pushing the buttons.

Another possible problem is the motor that moves doors inside the ducts to channel the air where you want it. Same comments as above.

Interesting question - If a mime dies, does anyone hear it?
A more relevant question - If a mime dies, does anyone care?

 

 

Thanks for the info. If it happens again I can check continuity of the switches.
Not a fan of mimes either.