I have a 04 Silverado crew cab with automatic AC. After many dead battery problems, the AC blend doors quit working correctly. If I pull the fuse and then let them reprogram, it may take several tries but I can eventually get them to work correctly. The problem then is that it only lasts for a couple of days. Any help on how to program these correctly would be appreciated.
That may be a tough problem to solve for a diy’er. What happens is the door motors, which are usually some kind of servo-design, they loose lose their “home” orientation, and get confused about what position they are in. It’s interesting yours seem to be able to learn it again then forget it again. My guess is that it will require the use of a scan tool that has a “servo-home” function. GM dealership shops will have it, but unsure who else.
I am on a trailblazer forum, this was suggested as a solution
I like pulling the fuse idea better than the battery diisconnect, good thinking!
“The HVAC system lost its calibration when the battery died. In order to recalibrate it, do the following;
Set all HVAC controls and switches to their OFF position or full CCW positions
Disconnect the battery for about 3 - 4 minutes
Reconnect battery, don’t move any HVAC controls and start truck
Let it run for about 3 - 4 minutes, then try the HVAC system.
If it still is not functioning correctly, there may be a stuck door or bad actuator.”