Not sure if anyone else gets this problem, but lately its been getting worse. I'll turn on my a/c to "MAX" and it will blow through the defroster first~then the front vents. The time between the switching is increasing every day. I used to start the car, put my bag in the back seat, get in and it be frosty. Now, I make it 3 blocks down the street before it blows through the front vents.

 

Usually these issues are vacuum related. There is a vacuum line than runs to the controls - the vent routing 'doors' are operated by vacuum - whena position on the switch is selected, the vacuum is rerouted to open or close that 'door'.

Check to see if there is anything like a kink in the vacuum line, or a loose vacuum connection on the back of the controls, or a cracked vacuum connector on the controls, etc. You may need to get a new set of controls if the housing on the back where the vacuum gets ported is cracked.

 

Good call. Nothing was cracked or kinked, but played with it and found a leak. As I'd put under "max" the rotating disc would seperate just enough to let out the vacuum. Bastard plastic...

 

Glad to help.