I recently had to replace my fuse box because one of the fuses had blown and damaged the contacts; a previous owner had actually placed a 10A fuse in a 15A slot, it was half melted! First I knew about it was when one of my headlights suddenly stopped working, lord only knows how long the fuse had been that way! Anyway, I digress.
Getting all of the spade connectors out of the fuse box was a fiddly task, and in the end I just chopped the thick green and white wire and used a 240v electrical joining block (the type with a brass tube and two screws) to join the new to the old. The rest of the connectors eventually came out OK and were quite easy to put in again to the replacement fuse box. There is a little tab which holds them in place, this has to be moved back with a small flat screwdriver before the connector can be pulled out downwards by the wire.
I created a diagram to show which wires go where.
Before being able to remove any of the wires there are two plastic grips which must be removed: a white plastic one which can be eased out using a small flat screwdriver (comes downwards when looking at the diagram), another is underneath the other connectors and is blue; this has to be teased out one clip at a time and requires some patience… getting it back in is twice as hard though!
It should be noted which wires go where (digital photos are good, but notes are useful too) in case there are any discrepancies in colour codes from what I have shown here, however it should be obvious which of the thick white/red wires go where as the spade connectors only fit certain holes.
Note also the difference between the two red wires – one has closely spaced silver stripes, the other has widely spaced silver stripes. I put a tie-wrap around one for easier identification.
The upper-most thick white/red wire on my diagram is a permanent fixture between the right and left hand side, this and the thick white/green wire may as well be left in place as I could not see a feasible way to remove them. My replacement fuse box already had one in because it came from a scrap car, I just joined the white/green wire to the one already in my engine bay (after cutting off my old fuse box from it).
Replacing the connectors and grips is just the reverse process used to take them out, although as already mentioned the blue grip is an absolute pain to get back in. I worked it in with the wires already in place, but it may be possible to place the wires through it and push the lot in as one piece.