I thought that I would post this to see if anyone has had this same problem. After changing to heat/defrost the other morning I have noticed a motor sound along with a slight clicking noise/light thumping noise coming from the air box under the dash. It sounds like it is the blend door for the heat/ac. It is switching between heat and ac just fine, but it is making strange noises. I am thinking that it is the blend door actuator that is going out. Does this sound like a likely scenario? Does the actuator just slide over the door shaft? Are there gears inside the actuator, or on the shaft? I didn't think that the blend door is faulty, but that it probably lies in the actuator. Thanks in advance for any information.
Sincerely,
Matt