After removing the dash in my 1999 tahoe I found the reason I was not getting heat on the floor was the divertor flap was out it its holder with the control arm disconected. I put the flap back in place and reatached the arm. My question is what holds the flap in place? I couldnt see anyway or preventing it from happening again. It is working now but whos knows how long. Must some sort of clip that came out or something. Thx for any help.

 

Quite possibly it is a push-on clip that looks like a washer but you can push on but it won't come off. If there is a groove, then it might be a C-clip or E-ring that slides on.