There's one last step before you're done. You must calibrate the actuator with the cars HVAC control system. This is because the car doesn't know the orientation of the new actuator. The procedure for this is as follows.

Reconnect the battery for the car, verify that you can start the car.

While the car is off, remove the 10A HVAC system "DIC/RKE" fuse from the passenger side fuse box. Let the car sit for at least a minute.

Reinstall the fuse and start the car, do not touch any of the climate controls. Wait at least a minute while the car relearns the actuator positions.

Turn the car back off, wait at least 10 seconds, and then start it again. The relearn procedure is now complete.

This part of the process is correct for 2000-2005 Monte Carlos, the calibration procedure for the 2006 and 2007 models is probably slightly different, as those cars have an entirely different set of fuses.