I replaced heat and blend door actuator’s on my 2007 Chevy impala and I still have clicking.
On a 2007 Model Impala GM service information only lists being able to perform a recalibration with a scan tool. In prior year models you could remove battery power from the HVAC control panel by removing a fuse for at least one full minute. Using that philosophy you could try removing the Display fuse in the underhood fuse box for one full minute and then reinstalling it. Turn the ignition on for 2 minutes and do not touch anything. Turn the ignition off for at least 10 seconds but no more than 30 seconds. Start the engine and test the HVAC operation.
I must point out though that if there is a steady clicking noise you likely still have a broken actuator somewhere. There are a total of 4 actuators in the vehicle. Of those four, three are prone to failure. The driver’s temperature door actuator, the passenger temperature door actuator and the fresh air inlet actuator.