Dodge Repair: how to locate and replace the blend door., dodge ram 1500, audible noise

Question
I have a 2001 Dodge Ram 1500 2X4 5.2liter engine, I suspect that the blend door in the a/c system is not operating right, how do I go about locating and repairing this component if it is malfunctioning? My a/c blows cold then will instantly switch to hot at various times, there is an audible noise from inside the dash right before blows hot. When i turn the system off, it seems to reset and blows cold when I reactivate the system only to change back to hot at any given moment.

Answer
u would haft to remove the dash and hvac box inorder to replace the door.  The fact that it gets cold for a second then hot  that's not a door  the door does not move unless u change it on the ac control head.  is the ac clutch still turning when u have the ac on?  if not  U need to look into that area not a door.