Heater Air Reduced Once Warmed Up

[bubbbab]

Hi folks:

This isn't for our 2003 PT, it's for Dad's 2007.

So, when he starts up everything is fine. BUT, once the car warms up, air flow diminishes to almost nothing and the Selector Dial for Feet, Defrost, cabin etc feels like there is no "click" from position to position. Both of these symptoms occur together and ONLY once the car gets warm, (15-30 minutes run time). The car (2007 Base) has A/C.

Any comments at all would be greatly appreciated.

Best,
Steve.