99-Sub

I have a 1999 Suburban and air always comes out of the defrost vest no matter what setting it is on. It changes from vent to floor, however on both most of the air comes from the defrost.

The mode actuator is moving fine and changes modes. I follow the arm off the actuator (looks as if the actuator runs 2 flaps) up and this bar is loose and I can move it all around. I am sure this should not be happening and also assume this is the door for the defrost vents.

I know at this point is sounds like I am answering all my own questions, just wanting to confirm I am on the right track here. Also seeing this door is just flopping around does anyone know if it is possible to get it reattached with out have to take the whole dash and heater box out?

I am almost positive I know the answer however am hoping someone will make my weekend by telling me a simple solution. I have the dash out on my other vehicle to replace the heater core and really don't want to pull another dash