AC starts cool, something clicks and then blows warm

Hopefully this is the correct forum to ask this question. My Google Fu is weak searching for a solution.

So here's the pattern. Start up the AC it blows nice and cool and at some point something "clicks" and it sounds like a baffle closes behind the dash and then it starts blowing warm air.

The "fix" for now is to turn the Temp knob all the way to Heat then back to Cool and the AC switches back to cool. Repeat after "a while" defined as several minutes but usually only once in my 12 - 15 minute drive to or from work.

I've had the coolant checked and it shows fully charged, so, any ideas from the guru's?


DG

2003 Tacoma Extended Cab, 4 Door, V6, very small bed (Dad wouldn't call it a truck!)

 

Sounds like a blend door issue. Not sure what system is in the 03's though.

 

Thank you for the start. At least I have something to research and maybe (horrors!) fix myself!
Since my "go to guy" for all things AC related is no longer available except via seance (I may need the services of the Long Island Medium!), I have not found another that I completely trust. Sad--- :-(

DG