[Tigers] passenger side vent control flap

[genepadgett at comcast.net]

My passenger side vent control flap has come totally disconnected from whatever it used to be connected to inside the box. With my dash now out of the car I have decided it is finally time to fix it, if I can. Rather than take my totally fine driver's side box apart to see how things are attached there, I thought first I would ask if anyone else has encountered a similar problem and can recommend a fix for it.. 


It looks like I can drill out the blind rivets on the front of the box and get to the flap. At the moment I cannot see any pivots on the flap. I am wondering if it somehow attaches to a flat piece of what looks like spring metal somehow attached firmly higher up in the box. On the driver's side the flap moves solidly from open and closed with a firm snap, so it must be spring loaded somehow. Not seeing anything loose in the box other than the flap, maybe there is something down the drain tube...? 


Any and all help will be greatly appreciated, thanks in advance. 


Gene