I dont believe that fuse is normally hot.
Basically, the computer has input to shut the low speed fan off, and requires input to turn high speed on. This is a safeguard so that if the ECT is open or the puter has an issue, low speed should come on.
The EDF relay control is a solid state device.
Are you having issues with the fan?
I ran through a lot of diagnostics myself, to find that the computer wasn't toggling me from low to high speed when AC was turned on. The circuit pathways are a little convoluted to troubleshoot because of the EDF control.
Good luck.