electronic air front and rear ac will not come out dash vents most of the time on 2003 Chevrolet Tahoe

more often thru the defrosters

Asked by for the 2003 Chevrolet Tahoe
Customer Concern: The air flows from the defroster duct instead of the center vents. Can hear a popping noise in the dash at this time. Manual system.

Tests/Procedures: 1. Feel the mode actuator by hand. It is on the left side of the Heating, Ventilation and Air Conditioning (HVAC) module.

2. Replace the actuator if it grinds/pops on the inside.
Tech Tips: The actual door position is not near the commanded door position. The HVAC control module does not command the actuator to move for the remainder of the ignition cycle.

Perform the calibration procedure for HVAC door actuators.
Remove the HVAC/ECAS fuse for a minimum of 10 seconds.
Install the HVAC/ECAS fuse.
Start the vehicle.
Wait 40 seconds for the HVAC control module to self-calibrate.