cant the box just be tested rather than jumping in like a d.i.y dave? when the fuel relay went a while ago everthing game up fine when the aa man poked around,
iv ran it around my head a few times now, so i'd basically be replacing the bbob boxholder and re joining the the cables as far back as possible regarding the state of the wires, in effect not a total rewire, therefore this would only solve any issues regarding the relay holder, yes?
1st of all it's not really a box, more just relays clipped into the engine bay with a black plastic cover, you don't replace the box. The parts can be tested to an extent if you're properly good with a test meter.
If the AA man poking around is the difference between the fuel pump running or not, then the BBoB does
need sorting, and is 90% likely to be the cause of your current woes.
The wires to the relay and fuse holders there go back under the battery about a foot, then they T into the rest of the loom. You'd replace all relay and fuse holders to save going back in when the next one goes.
The procedure would be.
1: Obtain replacement sockets/holders with wire. And get some new/clean relays and fuses (the relays out the fiat dashes are the same as the plastic top TS's 2 relays).
2: Remove battery and battery tray.
3: Cut old sockets/holders out of loom about 5-10cm back.
4: Strip the ends on the loom, and cut back more if there's any significant corrosion present still. Don't go back more than you have wire on the new bits.
5: Strip and Tin all ends.
6: Put a length of heat-shrink onto each wire then solder on the replacement pieces.
7: Shrink the heat-shrink.
8: Clip the sockets back onto the metal plate.
9: Pack the wires back into the plastic seething, use lots of electrical tape to seal it up as much as you can.
10: Replace battery tray and battery.
It takes about an hour.