Hello my name isXXXXX the shop manual the main heater does not show a heater control valve or auxiliary, what kind of problems are you having?
When you say you see temperature blend door move, this door is in the housing controlled by an actuator. Here is a picture of the actuator, try tapping on this actuator and see if it tries to work, if the hoses are both hot , you should have hot air if the door is in the right position, there is a possibility the blend could be broken or stuck inside the plenum. Here is a TSB I found check your build date and repair history and see if this has ever been done or if it even falls in the time frame. Hope this helps, Thanks Steve W, any more questions just ask.
1. The heater only controls air flow through the heater core, this is done electrically by the temp switch wired to the temperature blend door. This door is inside plenum, you can't see it, I wasn't for sure even if you can see actuator because they are hard to get to.
2 The temperature setting on the dash is wired to the blend door actuator all electric, these are known for going bad also.
I think the door you are looking at is another door, not the temperature blend door.
Here is some more info and description from shop manual.
Air Management Doors
The air management doors are controlled by vacuum control motors (18A318), a vacuum control motor and an A/C electronic door actuator motor (19E616). The air inlet and distribution doors are controlled by a vacuum control motor. The temperature blend door is controlled by the A/C electronic door actuator motor.
The A/C electronic door actuator motor provides a variable number of temperature blend door positions. The temperature control position energizes the A/C electronic door actuator motor, moving the temperature blend door.
Vacuum control motors are used on both air distribution and air inlet doors. The air inlet and panel doors use two-position vacuum control motors. The floor duct/defrost door uses a three-position vacuum control motor. Vacuum control motors are controlled by engine vacuum through the climate control head.