Chevrolet Repair: heater control problems, chevrolet 4x4, air doors

Question
Good evening Van.....I have a 1992 chevrolet 4x4 K2500 truck... about 3 weeks ago my heater control panel went out, I figured since this truck is 13+ years old the easiest fix would be to replace with a new item.  I purchased one from the local chevy dealer and it appeard to have solved the problem.  Yesterday however again the heater control panel is not working, and I believe I hear what sounds like a relay switch behind the dash 'clicking'with the key in the on position.  I have checked the fuse panel, unplugged the controller and replugged it back in and still am unable to get this to work.  any suggestions would be greatly appreciated.

Answer
Hi John,
The air doors on that unit are operated by little electric motors, called stepper motors. There are three of them, and the one you hear is right behind the dash, near the ash tray. it is held in by two screws, and slips onto a shaft. The little motor has a feedback system in it to tell the control module the position of the door.
Inside the motor box are some plastic gears. Stripped gears are what I have seen, and replacement is the cure.
If it keeps clicking, sounds like it is stripped, and can never reach where the control module is telling it to go, so it just keeps trying.

Van