The fuse boxes did have a tendency to burn up internally as the tiny pin connectors would get done in by the high current draw of the fuel pumps.
To bypass the fuse block do this. Here’s a pic of the stock pump relay located on the upper right of the block. Note the one blade that runs horizontally whereas the others run vertically.
With a pair of pliers bend that horizontal terminal outwards and plug it back into the fuse block. You should see the terminal protruding out from under the edge of the relay.
With the fuse block dropped down (remember, one screw and it’s only hanging by a couple of nubs) look back behind the block and you should see a connector in there that was once clear but is now probably yellow due to heat. There should be 3 wires (all green with black tracers if memory serves me right) and that is the pump wiring connector.
Make a jumper wire about a foot or so long with a couple of female spade connectors on each end. Plug one end onto the exposed relay terminal and the other into that yellowed connector after removing the single wire that runs to that connector from the fuse block. This will bypass the fuse block/connectors entirely and should never be a problem again.
I used to do these all of the time and got to where I could do them in 5 minutes or so.
You might examine the radio antenna grommet inside of the left front fender also. There were some problems with rain water leaks past the grommet and into the fuse block connectors. Your car should be fine, but if it looks shaky goop it up with some RTV silicone.
Some of the cars with manual transmissions have been known to take off cranking on their own during a thunderstorm after water leaked in and shorted the starter wiring. They would usually stop when the battery was dead, the starter burnt up, or the car ran into something…
Hope that helps.