On my 55 ford when I move the heater controls one of the cables comes off the post of the heater control. The other ones that push on are fine.

Timmy,Check and be sure that cable is not seized up.Check what it controls and make sure that it is not stuck.If the cable is sticking or hard to move they can be freed up with some oil.You may have to take cable out to do it.

  

The '56s have a clip that goes on the cable (outer sleeve at end) to hold it in place and keep it positioned, etc.  Not sure if 55 are the same, but i would imagine they have similar clip.  Assuming that is there, frozen cable is likely culprit

Ron Grove

Wauconda, IL