1999 Chrysler Concorde- Interior heat on max heat works fine, but as soon as I command the temp to decrease at all the air coming out of the vents drops dramatically(15-20 degrees), I've removed the blend door actuator and It seems to be moving close to the same amount as the command. I know there is a TSB on issue about replacing the BCM, I'm just trying to confirm

probably dust, crud, doghair gettin' into the mechanism. We should not seek a high-tech solution to a low-tech problem-

In the door blend actuator itself?

got to study your mechanism...gimme a sec-

okay...wow this looks like a small rhinoceros. still if you approch the ports and blast them clean with high pressure air we may be able to restore operation here...just a thought...also to get another from pickNpull doesn't seem that hard at this point if it will pull you up out of the grave-

The computer turns on the actuator motor and moves the blend door to the upper opening. The computer keeps the motor on until the tension on the motor causes the amps to rise. The computer reads the rise of the amps and now knows where the upper opening is. It repeats the same process for the lower opening. The computer now knows where both the upper and lower openings are. Along with the sensors and the temperature the system is set at, the computer can adjust the blend doors to let the proper amount of air flow thru the heater core or bypass the heater core to blend the air to the preset temperature. Depending on how often you use your vehicle, the calibration force could break off the stop tab within a few years. The only thing that breaks on the drive connector is the stop tab that is located outside of the heater box. The shaft of the plastic drive connector does not break. After the stop tab breaks the force of the actuator motor is now transferred to the shaft of the drive connector. As the blend doors do not break at the next calibration point after the stop tab broke. There is an undetermined period of time that could be months or it could be years. During that period of time the actuator motor is putting tension on the drive connector that is in turn putting tension on the blend doors. During these calibration times the full calibration force of the actuator motor is put onto the drive connector shaft and onto the blend door shaft. What ends up happening is the blend door shaft will break.

No Dash Removal repair for the back drive connector, for the VERY REMOTE chance the back drive connector did fail.

David mine is not like the pic above. The actuator has a protruding gear and it inserts into a female part of housing to to move the door. Any more thoughts