Edit: All is good now. My suspicion was correct; some sort of debris, likely from the clock trim, was jamming the actuator motor. I was turning my AC on/off to get the gears going and I finally heard something fell off the motor and now the knocking noise is gone.

Hey there G35Driver community. It has actually been a while since I've posted here, but I still have my Infiniti G35 and loving it. Currently hit 270,000 miles not too long ago. Been spending a lot of money recently getting it all maintained and hope to get a few more years out of it. However, I'm having an issue that I hope someone here can help. I'm currently experiencing a loud knocking noise coming from the Blend Door Actuator. I'm not sure if it's the result of some debris that dropped through the clock trim last week when I was getting some work done, but a week later I'm now hearing this knocking noise. The only way to fix it is to keep my AC on with cold air. I've dropped the cabin filter and I can see the actuator opening and closing as I turn the AC on/off. Does anyone have experience with this issue, and if they have a better solution? Or is replacing the actuator the only solution? I'm hoping it's not debris that fell through the clock trim blocking something causing the motor to knock.