How do you remove the fuse box in a 2002 f250

The one under the dash or under the hood?

under the dash

i just had one out the other day but it was on a newer model. i think there was just four bolts. and you have to take off the battery feed so make sure you remove the neg. battery cable so you dont short it out on any metal under the dash. you can pull it out just far enough to start unplugging connectors and then it will come the rest of the way.

does the harness plug into the fuse box or unplug somewhere else

there should be multiple plugs in the back