that is a lousy design, iv had 3 problems with this setup.
1. as mentioned cable issue (stuck in sleeve, kinked, end broke off)
2. door on the ac box gets stuck or packed with crap and it wont move
3. the knob has a metal sleeve inside the plastic socket where it fits on the the stud (hard to describe) but the wall of the plastic socket broke out and the sleeve now spins around.
these parts are pretty easy to come by in the local junkyard so Ive not had much problme in replacing them when they broke. but it is an annoyance... for the longest time i just reached up under the pass side dash and moved the lever back and forth by hand (when the cable was busted). for the knob issue I jsut pull off the temp knob, pull off the fan speed knob and use the fan spped knob to change the temp, then put em back (havent found a new knob yet).
Good luck!