A/C blows hot on drivers side

when ac is on all of a sudden the drivers side starts blowing hot air. if you turn the truck off then back on it works fine again. it is getting worse (more often). is this problem the blend door actuator? can i get it aftermarket? i talked to the local gm dealer they told me it was the temperature control actuator $285.00 from them. i cant find anywhere aftermarket that calls it that. wanting to know if its the blend door actuator

thanks