If you just want air to come out of the roof vents, put the control into that position, then when you get air out of the roof vents and the clicking starts, just unplug the actuator..Voila! No more clicking. I did this on mine until I could install a new actuator.
After learning that I couldn't simply leave it off, I did this and it worked. The actuator arm doesn't move and I now have it permanently on the roof position.