Door locks

My back slider doors do not lock or unlock with key fob or from driver or front passenger auto lock.( I can hear the lock) The locks will work manually. When motor is started locks click on and off, on and off. Battery has died a few time in last couple of months. One dealer(Kia) says latches have to be replaced in back passenger doors only and maybe controllers too. Another place says all door actuators must be replaced. What should I have replaced? Latches? Actuators? Controllers? On which doors?