Q: the sliding door lock in frozen in the locked position is this an indicator that the actuator needs replaced?

There is a motor in the lock actuator. Premature wearout of the motor is a known reported issue. The testing consists of ensuring that power is being delivered to the actuator, that is ensuring that the electrical connections to the actuator are good and tight. Also, you want to check and be sure all the mechanical linkages in the lock mechanism are free (nothing binding or corroded). With good electrical connections, if the actuator does not release the lock when you apply power, then it is faulty, To perform all these tests and checks, you have to remove the inside panel of the door. If you want the required diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, along with replacement of the lock actuator if warranted, please request door lock actuator service. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.