Completely out of options for AC blend door repair

[ctrout]

Please tell me what I have overlooked.

I have a 2003 Century with dual zone, manual control air conditioning. The blend doors were not working. They would move slightly, but only occasionally. Very intermittent and unreliable. Air temperature from the vents was pretty much always lukewarm. I replaced the actuators with new ones and the new actuators don't function at all, no motion whatsoever. So I did a system reset, several times. Still no movement from the actuators. So I removed them and applied power and ground to the appropriate pins and the actuators function correctly. At this point, I assumed the problem must be in the control head so I ordered a brand new one. Installed it and did another system reset and still no movement from the actuators. While doing the reset, I of course confirmed that both of the AC fuses (10A and 15A) behind the passenger side dash are serviceable. Edit to add: the doors themselves turn freely, just no movement from the actuators.

 

[ctrout]

Please tell me what I have overlooked.

I have a 2003 Century with dual zone, manual control air conditioning. The blend doors were not working. They would move slightly, but only occasionally. Very intermittent and unreliable. Air temperature from the vents was pretty much always lukewarm. I replaced the actuators with new ones and the new actuators don't function at all, no motion whatsoever. So I did a system reset, several times. Still no movement from the actuators. So I removed them and applied power and ground to the appropriate pins and the actuators function correctly. At this point, I assumed the problem must be in the control head so I ordered a brand new one. Installed it and did another system reset and still no movement from the actuators. While doing the reset, I of course confirmed that both of the AC fuses (10A and 15A) behind the passenger side dash are serviceable. Edit to add: the doors themselves turn freely, just no movement from the actuators.

Problem solved. The parts store sold me the actuators for the automatic climate control system. Exchanged them for the correct part and all is well. The strange thing is, they appear to be identical. Must be a difference in how the pins are arranged, or in the circuit boards inside or something.