lose of vacuum usually puts the air flow through the defrost only, when the blend door has a problem, Most of the time it causes the opposite, all heat, no cool. I bet the heater core is still plugged,feel both the heater hoses. If 1 is cooler then the other,it's restricted. Try reversing the hoses on the heater core,and drive it a few days. the heater core doesn't know directions.