Turn on heat, passenger side blows at requested temp, driver side blow

[MrConwayTwitty]

2010 GMC, As title reads, Had a bit of a cold morning with condensation build up on windows. Turn on heat to find that my drivers side vents are blowing air at or around the outside air temp. While Passenger side blows air in accordance with thermo temp setting at Heat/AC control panel. About 1.5 months ago I had a problem where my AC drain tube was completely plugged up so I was getting water in the cab of the truck from underneath the dash. That issue was resolved and AC worked fine again.

 

Any suggestions on where to begin? (other than calling a mechanic)

 

Thanks

[gmtech4]

you have a scanner ?

[txab]

Maybe actuator. Warranty if available