2001 GMC Sierra Air vent selection problem

Hi,
When I select 'dash only' position on the vent selector knob something behind the dash starts clicking (about 2 per second). If I select a dash vent/floor vent mix (10 o'clock on selector knob or second position) there is no clicking. I removed one of the actuators (passenger side near center console and inboard of the motor and filter) opened it up and found no visible issues. I closed it back up and reinstalled it. I previously could not change vent position and didn't get air out of any vents but after reinstalling actuator I get air out of selected vents but clicking continues in the dash vent only position. Also if I have outside air selected and vent select knob in any of the defrost positions and I try to switch from outside to recirc, the recirc light ion button flashes and stays in outside air. That doesn't happen with other vent positions selected. Do I need to reset the HVAC system? I have read online that sometimes that corrects these types of problems but cannot find the reset procedures. Thanks for any help you can provide. You guys are awesome!