Blower motor doesn't work, replaced harness, replaced transistor, tested existing blower by battery, tested another blower, any ideas???

Could there be a problem with the a/c-fan $ contol switch?

 

you tested a different blower and it still doesnt work? If so then i would check the control switch.

 

HOw do I go about testing the switch?

 

power at fuse box? then test along the system till you reach the dead zone

is it a NAV equipped car with electronic control or the regular dash with basic 3 position fan speed switch?
remove switch and see if there is power to it, and power coming out

Was any wiring damaged when you started this project? reason for all the parts?

 

existing blower test at batt- you hot wired to fan and it worked?

suspect switch