A mechanich checked to see why my blend door was swinging over to the heat mode when I was using my AC and informed me that the actuator and motor was working correctly in the AC mode but said that in the heat mode the door actuator did not stop. He said he counted 6 revolutions of the blend door when in the heat mode. He said the problem was with the door inside the HVAC housing and recommended removing the heater housing to inspect the blend door. Does anyone have any thoughts regarding this recommendation as this course of action didn't make sense to me.