The cable pull assembly that is attached to the bottom of the lock cylinder is made of plastic and the internal parts like the cable pull hook is thinner than most people's fingernails. Usually the very tip or the hook will break off with a slight snap or pop. if this has occurred, you must replace the whole cable assembly which includes both cables and the cable pull housing. The cables are stainless steel and it's not likely they they have broken. They will probably outlive the truck, but the plastic parts that the key lock turns to pull the cables is the real culprit.
....Rich