Heat/Cold control knob not working

[DavidTR]

my 2004 KZN165R recently developed an issue with the climate control dial that regulates hot and cold temperature. At first it would only turn about 1/4 of the distance of the dial range (see Dial video). Taking the face penal off it was turning around to the right until it hit the limiter tab on the dial, but when turning back towards left it would also stop but not due to the dial but a clunk sound coming from down at the Temperature  control unit under the dash (still haven't been able to locate the right name and part number for this "Black Box"). See end of first video showing the unit making the sound and how the lever is not operating over full range. 

Steps I've taken. 

1. Took the cable off the lever at the bottom of the black box temperature control. Check cable and fine, however the dial still didn't turn the full range of motion. I deduced that i must have forced it previously and it had advanced past the physical limits of the dial. Giving it some force it clicked loudly and advanced slightly more to the left. I did this a fee more times until the near full range of motion of the dial has returned and the cable is sliding freely back and forth (so not a cable or dial issue).

2. Check on the action of the lever that swings some sort of switching gate/flap inside the black box temperature control (Lever Gate video). It was clearly hitting a limiting point which was the source of the clunk sound originally. IT is like the gate or flap is hitting against the wall of the black box. I assume it is meant to do this to some degree but it seems it is limited to a very narrow range of motion and doesn't let the lever swivel its full range of motion without considerable force. Forcing it just seems to make it bend to accommodate the track in the lever it is meant to follow. 

So my thoughts are what is the physical obstruction of the gate/flap, inside the black box that is limiting the lever from moving across its full range of motion, which then translates back up the cable to limiting the dial being turned its full range of motion. Is it fixable or needs replacements. 

What is that black box even called and the part number. And does it need a full climate control rebuild to get to it, is it a part that can be removed form the bottom of the whole climate control system.

Any thoughts from the brains trust?