Okay, after looking at the way they wired the system I am retracting both of those and going with the blower control switch or the wiring to the blower motor failed if you are sure the AC is clicking on/off as you select it and you do not have high speed on the blower.
That is because the 40 amp heater fuse in the diagram also powers the AC system and the clutch as well as the blower motor. The blower resistor pack is removed from the circuit when on high speed and the switch and wiring to the blower motor itself are the only two items left if the motor itself is new.
So if you can check and see if the AC is actually working we can go from there.
Image (Click to make bigger)
Monday, October 9th, 2017 AT 6:30 PM