Defrost control cable and arm

[REDROCKER652002]

OK, So here is the next in the series of never ending questions for my son's 69. The defrost cable, arm and diverter flap. It seems the little arm that the cable runs along to open and shut the flap to divert the hot air is very close to the firewall insulation. I think that, and also a worn or stuck cable seems to be keeping the flap closed and no defrost on the truck. Is that little arm supposed to be on the firewall side of the truck? If so, should it be so close that it is rubbing the insulation? That is the only thing I can see that is keeping it from moving up and down. Anybody have any photos of what it should look like? I have a new controller and cables I will be installing soon, but just wondering as I sit here and have a beer what the deal is? Thanks to all who may have any input. RR