Here's what I did. I had some black ABS plastic that I'm using for another project. It's about as thick as a plastic business card. Same as that Team Chevelle membership card Al sent ya! You can cut it with scissors. I cut two strips about 2.5" X 1" and inserted them from the back(inlet side)into the gap between the 3 horizontal louvers that move and the 2 vertical ones that don't. (Note: My dash is out of the car and the vents are out of the dash. When I did it, the 2 stationary louvers were horizontal.) Using long needle nose pliers, I wedged it in and pushed it forward until it pushed the louvers into the half circle notches. (Ya gotta snake it around the open-closed door but it will go) Then I super-glued the ABS into place. It's not great, but it works.I don't see any other way to fix them short of cutting the housing open and that seemed like more trouble than it's worth to me.