Q&A

Power is supplied to the blower motor fan through the fan blower relay on the Blue/White wire, you have verified that the power on the blue white wire is good, so the 40 Amp fuse to pin 3 of the blower relay is good and pin 3 of the blower motor (protected by the 10 Amp fuse under dash fuse box is OK.
If power is present Key On Engine Off on the Blue White Wire at the Motor, the Blue/Black wire is grounded by the "blower motor power transistor". With the glove box removed the power transistor is at the bottom left side of the glove box opening. The wires going to it are as follows, pin 1 blue/black from fan motor, pin2 blue/yellow is from heater control panel, pin 4 is a control from a transistor with in the heater control panel, pin 3 is ground on this unit.
Check resistance between Blue/Black and Blue/Red wires at unit resistance should be 1.4 to 1.5 kilo ohms, if not power transistor is bad.