Recently had battery changed....I recalibrated the HVAC but that did not work. There is a possibility that I pushed an A/C button before the calibration was complete. Could this cause the front vents to stop working?
GM products are known for this issue. It can sometimes be prevented by making sure all the HVAC controls are in the off positions. If you wait patiently for 10 minutes in the vehicle after turning it off you can hear the doors return to the home position. Of course this only works if disconnecting the battery was planned. If the vehicle has some age (5 years plus) the doors may not re-home. The gears attached to the motor strip or break in half.The good news is that this happens so often now the motors are inexpensive. The bad news is that some require removing half the dash to gain access. Is this the procedure you used? Remove the HVAC / ECAS-10A fuse for a minute. Replace it, and then turn on the ignition, run the truck for 1-2 minutes, then turn the truck off. Wait for between 10 and 30 seconds, and then turn the truck back on. Important to note that You shouldn't touch the controls through this entire process.