Trying to get the heater working

The next issue is with the heat-defroster actuator diaphragm. You may recall that the section of the case that it was screwed into was busted. I made a bracket at work and sprayed it with textured bed liner to mimic the finish on the case. Then screwed it into place on the box, put the selector in defrost mode to remove the vacuum source, marked and drilled the bracket and attached the diaphragm in the same position as original. When I applied vacuum to the diaphragm, I could see it was wanting to move but wasn't accomplishing it's task. I believe that the curved rod on the top corner, that I assume actuates a door, is actually in the raised position and applying vacuum should pull it down? It won't move. Is it already all the way down? Is my diaphragm mislocated? What am I missing? Thanks for your all your help with this!