03 ctd ,when sitting in traffic or cool outside a/c wont blow.......fans is blowing but no air from vents,turn it off for about 15 minutes or so and works fine for a while.anyone had this problem or know what is causing this. thanks

 

the blend door may be broken. this is a common problem on 03's and early 04's.

 

This has happened twice to my truck, and was caused by low refridgerant, due to a leak in the evaporator.
The low freon level causes the evaporator to freeze up...........thus no airflow, once you turn the A/C off the evaporator thaws out , allowing airflow.
The fist time the dealer replaced the evaporator under warranty at 35000 mls, the second time was at 60000, so I was on my own.
Guess they don't make evaporators like they used to .
You might want to check the freon, and see if is low