The actuator is kinda hard to get to, especially when a passenger airbag is present.
But your problem doesn't sound actuator related at all - unless there'* an error code reported by the climate control headunit (does the display blink for a while after the car is started?).
Seems to me that a vacuum line got disconnected somewhere. Check all vacuum lines in the engine compartment first, and then the pink one that goes around the ECM, right above the passenger feet, and then to the actuator (you'll need to remove the right insulation panel, the plastic panel above the passenger feet). All the lines draw vacuum from the throttle body. From there it goes to a vacuum tank that'* between the brake booster and the relay center on the firewall, and then to all the accessories.
You can definitely manually change the air flow by playing with the vacuum lines that controls the vent doors, once you get to the actuator.
Hope this helps