Blower motor won't run. Replaced motor and fuses. Nothing. Any ideas?

The only way to find out what the problem is , Is by electrical testing ! No just replacing part's . You need to look at a wiring diagram to see which fuse is for the blower motor , not randomly check all of them . https://youtu.be/2vmfxYg8LoY

Check the internal fuse of the blower ...this not on the main fuse panel...if you look underneath if the blower unit you will find the card fuse...it may be shorting or have water or corrosion on the pcb circuitry.clean or replace...if this does not cure it seems you have a slipping fan belt on the alternator or the alternator is starting to fail.

On Nissan vehicles, the blower motor gets power from the fuse box, and the resistor and fan speed control provide the ground circuit.
So you should be able to ground the motor and make it run if you have power going to it. Then you would need to check the resistor and fan switch. The high setting bypasses the resistor.

Could be a bad connection at one of the fuses, or a coincidence and has nothing to do with the fuses. It could be the blower motor, resistor, or a connection somewhere.
You would need to check the blower fuse for power with a meter and then the blower motor when it fails to run.

dose it crank at all ?

Before replacing the blower motor, you should have checked the motor's input wiring loom for power.
Do you have power here?

If you don't have power, then you need to check your blower switch output wires.

The blower motor itself or the blower motor resistordo the resistor its faulty

On your vehicle, if it works on low speed, that eliminates the fuse, the blower motor relay and the blower motor resistor. All of the parts of the resistor must bee good for it to work on low. The relay supplies power to the motor and the controls provide the ground, so if the motor runs at all, it is not the relay or the fuse. The only thing left is the switch. Fords are bad about burning the wire connector that conects to the switch. You will most likely have to replace the switch and the connector. Both of these parts are widely avaiable at most aftermarket parts stores.

the blower motor is at fault. replace the motor and look for water entry onto that area inside the vehicle, will save you in the long run

it's either a fuse or it's a bad blower motor, it could be a bad blower motor resistor but usually you'll get either high or low only, so if you have nothing on any speed, high low etc, and all the fuses are ok chances are it's your blower motor.