The blower motor has a couple of 20A fuses in the fuse box. The resistor in the airbox is bypassed on the high speed. To locate the resistor look at the passenger side towards the blower motor and is in the air stream.
Forget about the fuses, go straight to the blower motor resistor in the airbox. You can see it if you look upwards from the passengers foot well. it has an electrical connector connected to it with 4 wites going to it. It's held in by 2 screws.
Remove it and check it for continuity between the electrical connectors with a multimeter. if any of the connections appear as an open circuit (i'm at least one of them will be), buy a new one and replace it.