Hi guys, first post from a newb...my wife'* Buick has push button climate control that cycles itself counter-clockwise through the functions, including rear defrost in @ 2-3 second intervals. It registers a button push, but immediately resumes cycling until either it decides to cooperate, or, sometimes, when the engine is restarted. Occasionally, it works as advertised all day - maybe two - but goes back to it'* bad habit. Coincidentally, the computer behind the glove box was replaced just before this all started - could that be it? I've been told it could be the blend door actuator or the circuit board behind the control panel...any ideas would be greatly appreciated.

Sounds to me like the head unit for the HVAC has failed. This is the module that has the control ***** and buttons mounted to it on a face plate. You can usually find them on Ebay. Changing them is usually just a matter of pulling the surround bezel, 4 screws and disconnecting the electrical connectors.

I'll give it a go! Thanks, Roy