I have a 2008 Tahoe Ltz one day my ac would only blow cold out of driver side and controls wouldn't change from vent to defrost. So I replaced control module and all actuators as well as did the reset process. Its blowing heat on both sides but not as strong on passenger side also it still will not change vents or cool.
A new control module must be programmed to the vehicles, they are not plug and play. The Apple Car Scanner app can read BCM codes on IPhones. If you have one or access to a bi-directional scan tool, pull up the internal BCM codes. It will tell you which actuators are bad and why with the symptom code following like, B0413 61 or B0413 05.
Having said all that, your Mode Actuator is the likely culprit here, it's the one in the driver's footwell. Aftermarket sensors don't last, buy once, cry once, for GM OE/ACDelco, same box or wrapper with both numbers.