I lied, the actual cable moves but the spring on the end of the cable(drum side) is so rusty that it lost a lot of it's springiness so doesn't release fully. The work cars have the cables seize because they coating on the cable gets beaten off by gravel then it wears down to the cable, letting in water and rusting then sticking.
I haven't had to free too many siezed cables, if I did they were just temporary fixes. Soaking one in diesel might be worth a shot.