PontiacBonnevilleClub.com

I disconnected my battery to clean the posts. When I turned on the ignition the AC started up as it usually does after battery disconnections. The system had been working properly, but now it shows a code 40, Driver Air Mix Motor cirduit open or shorted or not calibrated. Each time I start the car I also hear the air mix door cycling very slowly. Sort of a groaning sound. Eventually the blinking indicator times out and the AC seems to work properly.

Here's the question - to I need to somehow readjust the air mix door? if so is it hard to get to.

There is a good chance the air mix actuator has failed (cracked gear). This likes to happen when power is removed then added back. It forces the actuator to go through the calibration process, finding the open and closed limits. This strains an old and brittle gear and causes it to crack. There is a write up in tech info for the air mix actuator.