The board that the fuse sits in is around $ 1000 (AUD) and the fuse is there to protect it.
I know that because I had to replace one, twice.
First one got replaced with a new one as it had corrosion all over the place & had been shorting at the relay bases due to build up of conductive dust . The second time I found a geek to fix it.
And yes the second time the owner who "just had to mow the grass" shoved a 40A fuse in there which apparently blew every hour or so and melted the fuse holder in the process.
The 445's ran for a very long time and are very good tractors, as you know cause you have one.
The down side of this is there are about 20 variations to the wiring diagrams so it is not going to be a simple case of "resolder the blue wire " job.
We really need the serial number after which I can find the right diagram & post it.
If you don't have the manual ( and your should ) start a new thread asking is some one has one they can send you.
Some on the list are very good about sharing manuals ( or part there of ) and some will have old ones they don't need.
Problem for techs doing it because we need to keep a good working relationship with the manufacturers & down here JD take a dim view of people who buy a manual the distribute it widely for free or profit.