I know this thread is old but I have the same problem with my wifes car. The hot / cold motor works fine. The vent actuator motor doesn't move at all for me and is stuck on the defrost position. I'm trying to determine whether or not it's the motor or the switch it self before I head to the dealer to have them work on it. Either way the actuator is ~$100

and whatever install would cost. Looks really hard to get to the vent actuator.
Definitely not a connecting rod issue as the only rods there are in the system are the ones connected to each actuator (motor) and all those are connected.
Digital_Reaper... Did you ever get the problem resolved on your car?