Also note that in the C and H bodies its very common for the Actuator to strip a gear and stop short of being dead cold.. Not nice to have the actuator break and cook you out of the car on a rainy day..
In the vid you'll actually hear the gears grind and creek.. With the actuator hooked to the blend door it made no noise.. Just got stuck on roughly 80F... With the manual controls the Actuator has electronics in it that controls Blend door position.. With the Electronic Climate Control the ECC head controls the Blend door position via the actuator.. So the below vid is one possibility for you..
