94 Doge Ram Diesel cooling Problem

Hello, I have a 94 Dodge Ram, 3/4 ton diesel. I had my mechanic put a new AC fan blower/motor in it. As it would get really cold, but the blower didn't work. Once you started driving, & turned the AC on, cold air would be pushed out the vents a little by the outside driving air. So it was deemed after checking electrical connections from the blower, that it was bad. Mechanic put new blower motor in today & the fan blows great out the vents, but no cold air. He put a thermometer gauge on the out side under the hood. It read 68 degrees from the compressor. But the air coming out my inside vents was reading 88 degrees, as it was 100 degrees outside temperature. What could he have done wrong? I don't hear that vacuum pop/suction sound anymore, that usually happens when I turn on the AC. He thinks it's the blender doors, but the fan is coming out correctly of all areas I turn my switch to. All my fan speeds are correctly working. So...do you have any suggestions?
Thanks for any thoughts on this...